DataListDesigner Class
.NET Framework 3.0
Extends design-time behavior for the DataList Web server control.
Namespace: System.Web.UI.Design.WebControls
Assembly: System.Design (in system.design.dll)
System.Web.UI.Design.WebControls Namespace
DataList
DataListComponentEditor
Walkthrough: Creating a Basic Control Designer for a Web Server Control
Extending Design-Time Support
How to: Extend the Appearance and Behavior of Controls in Design Mode
Assembly: System.Design (in system.design.dll)
The following code example demonstrates how to extend the DataListDesigner class. The code overrides the GetDesignTimeHtml method to display a five-point border that is purple if the DataList control is enabled.
using System; using System.Drawing; using System.Security.Permissions; using System.ComponentModel; using System.Web.UI.WebControls; using System.Web.UI.Design; using System.Web.UI.Design.WebControls; ... namespace ASPNET.Examples.CS { [SecurityPermission( SecurityAction.Demand, Flags = SecurityPermissionFlag.UnmanagedCode)] public class SimpleGridViewDesigner : GridViewDesigner { private SimpleGridView simpleGView; public override string GetDesignTimeHtml() { string designTimeHtml = String.Empty; simpleGView = (SimpleGridView)Component; // Check the control's BorderStyle property to // conditionally render design-time HTML. if (simpleGView.BorderStyle == BorderStyle.NotSet) { // Save the current property settings in variables. int oldCellPadding = simpleGView.CellPadding; Unit oldBorderWidth = simpleGView.BorderWidth; Color oldBorderColor = simpleGView.BorderColor; // Set properties and generate the design-time HTML. try { simpleGView.Caption = "SimpleGridView"; simpleGView.CellPadding = 1; simpleGView.BorderWidth = Unit.Pixel(3); simpleGView.BorderColor = Color.Red; designTimeHtml = base.GetDesignTimeHtml(); } catch (Exception ex) { // Get HTML from the GetErrorDesignTimeHtml // method if an exception occurs. designTimeHtml = GetErrorDesignTimeHtml(ex); // Return the properties to their original values. } finally { simpleGView.CellPadding = oldCellPadding; simpleGView.BorderWidth = oldBorderWidth; simpleGView.BorderColor = oldBorderColor; } } else designTimeHtml = base.GetDesignTimeHtml(); return designTimeHtml; } protected override string GetErrorDesignTimeHtml(System.Exception exc) { return CreatePlaceHolderDesignTimeHtml( "ASPNET.Examples: An error occurred while rendering the GridView."); } public override void Initialize(IComponent component) { simpleGView = (SimpleGridView)component; base.Initialize(component); } } }
The following code example shows how to use the DesignerAttribute to associate the designer with the DataList control.
- SecurityPermission for calling unmanaged code. Demand value: Demand. Permission value: UnmanagedCode
Reference
DataListDesigner MembersSystem.Web.UI.Design.WebControls Namespace
DataList
DataListComponentEditor
Other Resources
Introduction to ASP.NET Control DesignersWalkthrough: Creating a Basic Control Designer for a Web Server Control
Extending Design-Time Support
How to: Extend the Appearance and Behavior of Controls in Design Mode
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