The user can also add rows and edit cells. Parent tables are the highest level of data, and child tables are those data tables that are derived from the individual listings in the parent tables. Expanders are displayed in each parent row that contains a child table. Clicking an expander generates a list of Web-like links to the child tables.
When the user selects a link, the child table is displayed. The user can click a back button to move back to the previously viewed table.
You can edit the TableStyles and GridColumnStyles properties by using collection editors accessed through the Properties window. Table styles and column styles are synchronized with DataTable objects and DataColumn objects by setting their MappingName properties to the appropriate TableName and ColumnName properties. When a DataGridTableStyle that has no column styles is added to a DataGrid control bound to a valid data source, and the MappingName property of that table style is set to a valid TableName property, a collection of DataGridColumnStyle objects is created for that table style.
A collection of column types extends the DataGridColumnStyle class with rich formatting and editing capabilities. All column types inherit from the DataGridColumnStyle base class. The following table describes each of these column types. Double-clicking the right edge of a column resizes the column to display its full caption and widest entry.
As soon as you have established the default format of the DataGrid control, you can customize the colors that will be used when certain tables are displayed within the data grid. This is achieved by creating instances of the DataGridTableStyle class. Table styles specify the formatting of specific tables, distinct from the default formatting of the DataGrid control itself.
Each table may have only one table style defined for it at a time. Sometimes, you will want to have a specific column look different from the rest of the columns of a particular data table.
You can create a customized set of column styles by using the GridColumnStyles property. Column styles are related to columns in a dataset just like table styles are related to data tables. Just as each table may only have one table style defined for it at a time, so too can each column only have one column style defined for it, in a particular table style. This relationship is defined in the column's MappingName property.
If you have created a table style without column styles added to it, Visual Studio will add default column styles when the form and grid are created at run time. However, if you have created a table style and added any column styles to it, Visual Studio will not create any column styles. Also, you will need to define column styles and assign them with the mapping name to have the columns that you want appear in the grid.
Because you specify which columns are included in the data grid by assigning them a column style and no column style has been assigned to the columns, you can include columns of data in the dataset that are not displayed in the grid. However, because the data column is included in the dataset, you can programmatically edit the data that is not displayed. In general, create column styles and add them to the column styles collection before adding table styles to the table styles collection.
When you add an empty table style to the collection, column styles are automatically generated for you. Consequently, an exception will be thrown if you try to add new column styles with duplicate MappingName values to the column styles collection. Sometimes, you will want to just tweak one column among many columns; for example, the dataset contains 50 columns and you only want 49 of them. In this case, it is easier to import all 50 columns and programmatically remove one, rather than programmatically adding each of the 49 individual columns you want.
Formatting that can be applied to the DataGrid control includes border styles, gridline styles, fonts, caption properties, data alignment, and alternating background colors between rows. Besides the common control events such as MouseDown , Enter , and Scroll , the DataGrid control supports events associated with editing and navigation within the grid.
The CurrentCell property determines which cell is selected. In edit mode, the content contained in the EditItemTemplate property is displayed for the current data item.
Typically, the edit item template is defined such that the Edit button is replaced with an Update and a Cancel button. Input controls that are appropriate for the field's data type such as a TextBox or a CheckBox control are also usually displayed with a field's value for the user to modify.
Clicking the Update button updates the record in the data source, while clicking the Cancel button abandons any changes. Likewise, the content contained in the InsertItemTemplate property is displayed for the data item when the control is in insert mode.
The insert item template is typically defined such that the New button is replaced with an Insert and a Cancel button, and empty input controls are displayed for the user to enter the values for the new record. Clicking the Insert button inserts the record in the data source, while clicking the Cancel button abandons any changes. The FormView control provides a paging feature, which allows the user to navigate to other records in the data source.
When enabled, a pager row is displayed in the FormView control that contains the page navigation controls. You can customize the pager row by setting the properties of objects contained in the PagerStyle and the PagerSettings property.
You can customize the appearance of the FormView control by setting the style properties for the different parts of the control. The FormView control provides several events that you can program against. The following table lists the events supported by the FormView control. The DetailsView control is used to display a single record from a data source in a table, where each field of the record is displayed in a row of the table. It can be used in combination with a GridView control for master-detail scenarios.
The DetailsView control supports the following features:. Each data row in the DetailsView control is created by declaring a field control. Different row field types determine the behavior of the rows in the control.
Field controls derive from DataControlField. The following table lists the different row field types that can be used.
By default, the AutoGenerateRows property is set to true , which automatically generates a bound row field object for each field of a bindable type in the data source. Each field is then displayed in a row as text, in the order in which each field appears in the data source. Automatically generating the rows provides a quick and easy way to display every field in the record. However, to make use of the DetailsView control's advanced capabilities you must explicitly declare the row fields to include in the DetailsView control.
To declare the row fields, first set the AutoGenerateRows property to false. The row fields specified are added to the Fields collection in the order listed. The Fields collection allows you to programmatically manage the row fields in the DetailsView control.
IEnumerable interface, such as System. ArrayList and System. Use one of the following methods to bind the DetailsView control to the appropriate data source type:. This control can be used to display user input, which might include malicious client script. Check any information that is sent from a client for executable script, SQL statements, or other code before displaying it in your application.
The DetailsView control provides built-in capabilities that allow the user to update, delete, insert, and page through items in the control. When the DetailsView control is bound to a data source control, the DetailsView control can take advantage of the data source control's capabilities and provide automatic updating, deleting, inserting, and paging functionality.
The DetailsView control can provide support for update, delete, insert, and paging operations with other types of data sources; however, you must provide the implementation for these operations in an appropriate event handler. Unlike the Delete button which deletes the selected record immediately , when the Edit or New button is clicked, the DetailsView control goes into edit or insert mode, respectively.
In edit mode, the Edit button is replaced with an Update and a Cancel button. Input controls that are appropriate for the field's data type such as a TextBox or a CheckBox control are displayed with a field's value for the user to modify. Likewise, in insert mode, the New button is replaced with an Insert and a Cancel button, and empty input controls are displayed for the user to enter the values for the new record.
The DetailsView control provides a paging feature, which allows the user to navigate to other records in the data source. When enabled, page navigation controls are displayed in a pager row. The pager row can be customized using the PagerStyle and PagerSettings properties. You can customize the appearance of the DetailsView control by setting the style properties for the different parts of the control.
The DetailsView control provides several events that you can program against. The following table lists the events supported by the DetailsView control. The Menu control in ASP. It can be databound easily to hierarchical data sources such as the SiteMapDataSource. A Menu controls structure can be defined declaratively or dynamically and consists of a single root node and any number of sub-nodes. The following code declaratively defines a menu for the Menu control. In the above example, the Home.
All other nodes are nested within the root node at various levels. There are two types of menus that the Menu control can render; static menus and dynamic menus.
Static menus consist of menu items that are always visible. Dynamic menus consist of menu items that are only visible when the user hovers over them with the mouse. Customers may often confuse static menus with menus defined declaratively and dynamic menus with menus that are databound at runtime. In fact, dynamic and static menus are unrelated to the method of population. The terms static and dynamic refer only to whether or not the menu is statically displayed by default or only displayed when the user takes some action.
The StaticDisplayLevels property is used to configure how many levels of the menu are static and therefore displayed by default. In the above example, setting the StaticDisplayLevels property to a value of 2 would cause the menu to statically display the Home node, the Music node, and the Movies node. All other nodes would be dynamically displayed when the user hovers over the parent node. The MaximumDynamicDisplayLevels property configures the maximum number of dynamic levels the menu is capable of displaying.
Any dynamic menus at a level higher than the value specified by the MaximumDynamicDisplayLevels property are discarded. It is almost certain that you might encounter situations where menus don't appear to render due to the MaximumDynamicDisplayLevels property. In those cases, ensure that the property is set sufficiently to allow for the display of the customers menus.
The SiteMapDataSource is the most commonly used method for data binding to a Menu control because it feeds off of the Web. The listing below shows a simple Web. Notice that there is only one root siteMapNode element, in this case, the Home element.
Several attributes can be configured for each siteMapNode. The most commonly used attributes are:. Note that while these attributes are all optional, the behavior of the menu may not be what is expected if they are not specified.
For example, if the url attribute is specified but the description attribute is not, the node will not be visible and there will be no way to navigate to the URL specified.
There are several properties that affect the operation of an ASP. Using these templates, you can easily add server controls or user controls to your menus.
To edit the templates in Visual Studio. Any controls added to the StaticItemTemplate will appear in the static menu when the page loads. Any controls added to the DynamicItemTemplate will appear on all pop-up menus. The MenuItemClicked event is raised when a menu item is clicked. The MenuItemDatabound event is raised when a menu item is databound. The MenuEventArgs that is passed to the event handler provides access to the menu item via the Item property.
You can also affect the appearance of a menu control using one or more of the many styles available to format menus. For example, the following will affect the style for dynamic menus. The TreeView control displays data in a tree-like structure. As with the Menu control, it can be easily data bound to any hierarchical data source such as the SiteMapDataSource. NET 1. It is not. The ASP. I won't go into detail on how to bind a TreeView control to a site map as it is performed in exactly the same way as the Menu control.
However, the TreeView control has some distinct differences in the way that it operates. By default, a TreeView control appears fully expanded. To change the level of expansion upon initial load, modify the ExpandDepth property of the control. This is particularly important in cases where the TreeView is databound upon expanding particular nodes.
Unlike the Menu control, the TreeView lends itself well to handling large amounts of data. In cases where the TreeView control is bound to large amounts of data, it is best to bind only to data that is actually visible in the control. You can then data bind to additional data as TreeView nodes are expanded. You will then need to provide an implementation for the TreeNodePopulate method. Notice that when you expand a node in the previous example for the first time, the page posts back and refreshes.
Thats not a problem in this example, but you can imagine that it might be in a production environment with a large amount of data. A better scenario would be one in which the TreeView would still dynamically populate its nodes, but without a post back to the server. NET TreeView control will dynamically populate nodes without a post back.
The server responds with an XML data island which is then used to data bind the child nodes. NET dynamically creates the client code that implements this functionality.
For example, the listing below shows the script links for the script code that generates the XMLHttp request. This method prevents customers from modifying the script file. The TreeView control has several properties that affect the operation of the control. The ShowCheckBoxes property affects whether or not nodes display a check box when rendered. These affect the TreeView control as follows:. When checkboxes are being used, the CheckedNodes property will return a collection of TreeView nodes that are checked upon postback.
The ShowLines property controls whether or not lines are displayed connecting parent nodes to child nodes. When false the default , no lines are displayed. When true , the TreeView control will use lines images in the folder specified by the LineImagesFolder property. To customize the appearance of TreeView lines, Visual Studio. NET includes a Line Designer tool. You can access this tool using the Smart Tag button on the TreeView control as below. When select the Customize Line Images menu option, the Line Designer tool will be launched allowing you to configure the appearance of TreeView lines.
The SelectAction property allows you to configure which event is fired when a node is selected. The SelectAction property provides the following actions:. The TreeView control provides many properties for controlling the appearance of the control with styles.
The following properties are available. Each of these properties is read-only. However, they will each return a TreeNodeStyle object, and the properties of that object can be modified using the property-subproperty format.
For example, to set the ForeColor property of the SelectedNodeStyle , you would use the following syntax:. Notice that the tag above is not closed. That is because when using the declarative syntax shown here, you would include the TreeViews nodes in the HTML code as well. The style properties can also be specified in code using the property. For example, to set the ForeColor property of the RootNodeStyle in code, you would use the following syntax:. NET developers.
Like the other navigation controls, it can be easily data bound to hierarchical data sources such as the SiteMapDataSource or XmlDataSource.
There are three types of nodes; the Root node, Parent nodes, and the Current node. The root node is the node at the top of the hierarchical structure. The current node represents the current page. All other nodes are parent nodes. NET 6 and. NET 5 including. NET Core 3. Data binding is the process that establishes a connection between the app UI and the data it displays.
If the binding has the correct settings and the data provides the proper notifications, when the data changes its value, the elements that are bound to the data reflect changes automatically. Data binding can also mean that if an outer representation of the data in an element changes, then the underlying data can be automatically updated to reflect the change.
For example, if the user edits the value in a TextBox element, the underlying data value is automatically updated to reflect that change. A typical use of data binding is to place server or local configuration data into forms or other UI controls. In WPF, this concept is expanded to include binding a broad range of properties to different kinds of data sources. In WPF, dependency properties of elements can be bound to. Regardless of what element you're binding and the nature of your data source, each binding always follows the model illustrated by the following figure.
As the figure shows, data binding is essentially the bridge between your binding target and your binding source. The figure demonstrates the following fundamental WPF data binding concepts:. For example, if you bound the content of a TextBox to the Employee. Name property, you would set up your binding like the following table:. Most UIElement properties are dependency properties, and most dependency properties, except read-only ones, support data binding by default. Only types derived from DependencyObject can define dependency properties.
Although not shown in the figure, it should be noted that the binding source object isn't restricted to being a custom. NET object. WPF data binding supports data in the form of. For more information, see Binding sources overview. It's important to remember that when you're establishing a binding, you're binding a binding target to a binding source. To establish a binding, you use the Binding object. The rest of this article discusses many of the concepts associated with and some of the properties and usage of the Binding object.
When data binding is declared on XAML elements, they resolve data binding by looking at their immediate DataContext property. The data context is typically the binding source object for the binding source value path evaluation. You can override this behavior in the binding and set a specific binding source object value. If the DataContext property for the object hosting the binding isn't set, the parent element's DataContext property is checked, and so on, up until the root of the XAML object tree.
In short, the data context used to resolve binding is inherited from the parent unless explicitly set on the object. Bindings can be configured to resolve with a specific object, as opposed to using the data context for binding resolution.
Specifying a source object directly is used when, for example, you bind the foreground color of an object to the background color of another object. Data context isn't needed since the binding is resolved between those two objects.
Inversely, bindings that aren't bound to specific source objects use data-context resolution. When the DataContext property changes, all bindings that could be affected by the data context are reevaluated. You may want your app to enable users to change the data and propagate it back to the source object. Or you may not want to enable users to update the source data. You can control the flow of data by setting the Binding.
OneWay binding causes changes to the source property to automatically update the target property, but changes to the target property are not propagated back to the source property. This type of binding is appropriate if the control being bound is implicitly read-only. For instance, you may bind to a source such as a stock ticker, or perhaps your target property has no control interface provided for making changes, such as a data-bound background color of a table.
If there's no need to monitor the changes of the target property, using the OneWay binding mode avoids the overhead of the TwoWay binding mode. TwoWay binding causes changes to either the source property or the target property to automatically update the other. This type of binding is appropriate for editable forms or other fully interactive UI scenarios. Most properties default to OneWay binding, but some dependency properties typically properties of user-editable controls such as the TextBox.
Text and CheckBox. IsChecked default to TwoWay binding. A programmatic way to determine whether a dependency property binds one-way or two-way by default is to get the property metadata with DependencyProperty.
BindsTwoWayByDefault property. OneWayToSource is the reverse of OneWay binding; it updates the source property when the target property changes. One example scenario is if you only need to reevaluate the source value from the UI. Not illustrated in the figure is OneTime binding, which causes the source property to initialize the target property but doesn't propagate subsequent changes. If the data context changes or the object in the data context changes, the change is not reflected in the target property.
This type of binding is appropriate if either a snapshot of the current state is appropriate or the data is truly static. This type of binding is also useful if you want to initialize your target property with some value from a source property and the data context isn't known in advance.
This mode is essentially a simpler form of OneWay binding that provides better performance in cases where the source value doesn't change. To detect source changes applicable to OneWay and TwoWay bindings , the source must implement a suitable property change notification mechanism such as INotifyPropertyChanged. See How to: Implement property change notification. The Binding. Mode property provides more information about binding modes and an example of how to specify the direction of a binding.
Bindings that are TwoWay or OneWayToSource listen for changes in the target property and propagate them back to the source, known as updating the source.
For example, you may edit the text of a TextBox to change the underlying source value. However, is your source value updated while you're editing the text or after you finish editing the text and the control loses focus?
UpdateSourceTrigger property determines what triggers the update of the source. The dots of the right arrows in the following figure illustrate the role of the Binding. UpdateSourceTrigger property. PropertyChanged , then the value pointed to by the right arrow of TwoWay or the OneWayToSource bindings is updated as soon as the target property changes.
However, if the UpdateSourceTrigger value is LostFocus , then that value only is updated with the new value when the target property loses focus.
Similar to the Mode property, different dependency properties have different default UpdateSourceTrigger values. The default value for most dependency properties is PropertyChanged , which causes the source property's value to instantly change when the target property value is changed. Instant changes are fine for CheckBox and other simple controls. However, for text fields, updating after every keystroke can diminish performance and denies the user the usual opportunity to backspace and fix typing errors before committing to the new value.
For example, the TextBox. Text property defaults to the UpdateSourceTrigger value of LostFocus , which causes the source value to change only when the control element loses focus, not when the TextBox.
Text property is changed. See the UpdateSourceTrigger property page for information about how to find the default value of a dependency property. The following table provides an example scenario for each UpdateSourceTrigger value using the TextBox as an example.
For an example, see How to: Control when the TextBox text updates the source. NET Framework. For an example of data binding, take a look at the following app UI from the Data Binding Demo , which displays a list of auction items.
The content of the ListBox is bound to a collection of AuctionItem objects. The data AuctionItem objects displayed in the ListBox is templated so that the description and the current price are shown for each item. The template is created by using a DataTemplate. In addition, the appearance of each item depends on the SpecialFeatures value of the AuctionItem being displayed.
If the value is Highlight , the item has an orange border and a star. The Data Templating section provides information about data templating. The user can group, filter, or sort the data using the CheckBoxes provided. In the image above, the Group by category and Sort by category and date CheckBoxes are selected.
You may have noticed that the data is grouped based on the category of the product, and the category name is in alphabetical order. It's difficult to notice from the image but the items are also sorted by the start date within each category. Sorting is done using a collection view.
The Binding to collections section discusses collection views. When the user selects an item, the ContentControl displays the details of the selected item. This experience is called the Master-detail scenario. The Master-detail scenario section provides information about this type of binding. The type of the StartDate property is DateTime , which returns a date that includes the time to the millisecond.
In this app, a custom converter has been used so that a shorter date string is displayed. The Data conversion section provides information about converters. The user can edit the fields in the form, preview the product listing using the short or detailed preview panes, and select Submit to add the new product listing. Any existing grouping, filtering and sorting settings will apply to the new entry. In this particular case, the item entered in the above image will be displayed as the second item within the Computer category.
Not shown in this image is the validation logic provided in the Start Date TextBox. If the user enters an invalid date invalid formatting or a past date , the user will be notified with a ToolTip and a red exclamation point next to the TextBox. The Data Validation section discusses how to create validation logic.
Before going into the different features of data binding outlined above, we will first discuss the fundamental concepts that are critical to understanding WPF data binding. To restate some of the concepts discussed in the previous sections, you establish a binding using the Binding object, and each binding usually has four components: a binding target, a target property, a binding source, and a path to the source value to use.
This section discusses how to set up a binding. Binding sources are tied to the active DataContext for the element. Elements automatically inherit their DataContext if they've not explicitly defined one. Consider the following example, in which the binding source object is a class named MyData that is defined in the SDKSample namespace. For demonstration purposes, MyData has a string property named ColorName whose value is set to "Red". Thus, this example generates a button with a red background.
For more information on the binding declaration syntax and examples of how to set up a binding in code, see Binding declarations overview. If we apply this example to our basic diagram, the resulting figure looks like the following. This figure describes a OneWay binding because the Background property supports OneWay binding by default.
You may wonder why this binding works even though the ColorName property is of type string while the Background property is of type Brush. This binding uses default type conversion, which is discussed in the Data conversion section.
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