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FormViewDesigner Class

Note: This class is new in the .NET Framework version 2.0.

Provides design-time support in a visual designer for the FormView control.

Namespace: System.Web.UI.Design.WebControls
Assembly: System.Design (in system.design.dll)

public class FormViewDesigner : DataBoundControlDesigner
public class FormViewDesigner extends DataBoundControlDesigner
public class FormViewDesigner extends DataBoundControlDesigner

In a visual designer, when you switch from Source to Design view, the markup source code that describes the FormView control is parsed and a design-time version of the control is created on the design surface. When you switch back to Source view, the design-time control is persisted to the markup source code and edited into the markup for the Web page.

The properties of the FormViewDesigner class provide the following functionality:

  • The ActionLists property returns a DesignerActionListCollection object, which typically contains an object that is derived from the DesignerActionList class for each level in the inheritance tree of the designer.

  • The AutoFormats property returns a collection of formatting schemes for display in the Auto Format dialog box.

  • The TemplateGroups property returns a collection of template groups for the templates of the associated FormView.

  • The UsePreviewControl property always returns true, indicating that the designer creates a temporary copy of the associated FormView to generate the design-time markup.

The FormViewDesigner class methods provide the following functionality:

  • The GetDesignTimeHtml method returns the markup that is used to render the associated FormView at design time.

  • The Initialize method prepares the designer to view, edit, and design the associated FormView.

  • The OnSchemaRefreshed method is called when the schema of the data source for the associated FormView changes.

The following code example shows how to extend the FormViewDesigner class to change the appearance of controls that are derived from the FormView control at design time.

The example derives the MyFormView control from the FormView control. The MyFormView is simply a copy of the FormView. The example also derives the MyFormViewDesigner class from the FormViewDesigner and places a DesignerAttribute object for the MyFormViewDesigner on the MyFormView control.

The MyFormViewDesigner overrides the following items:

  • The SampleRowCount property to specify that the pager row for the design-time view of the MyFormView contain four page links.

  • The GetDesignTimeHtml method to include the Caption property, if it is specified, as a new first row in the MyFormView grid at design time. If the BorderStyle property of the MyFormView is the NotSet or None value, the GetDesignTimeHtml draws a blue dashed border around the control to make its extent more visible.

using System;
using System.Web;
using System.Drawing;
using System.Web.UI.WebControls;
using System.Web.UI.Design.WebControls;
using System.Collections;
using System.ComponentModel;
using System.Security.Permissions;

namespace Examples.CS.WebControls.Design
{
    // The MyFormView is a copy of the FormView.
    [AspNetHostingPermission(SecurityAction.Demand, 
        Level = AspNetHostingPermissionLevel.Minimal)]
    [AspNetHostingPermission(SecurityAction.InheritanceDemand, 
        Level = AspNetHostingPermissionLevel.Minimal)]
    [Designer(typeof(Examples.CS.WebControls.Design.MyFormViewDesigner))]
    public class MyFormView : FormView
    {
    } // MyFormView

    // Override members of the FormViewDesigner.
    public class MyFormViewDesigner : FormViewDesigner
    {
        // Determines the number of design-time links in the pager row.
        protected override int SampleRowCount
        {
            get
            {
                // Render four links in the pager row.
                return 4;
            }
        } // SampleRowCount

        // Generate the design-time markup.
        const string capTag = "caption";
        const string trOpen = "tr><td colspan=9 align=center";
        const string trClose = "td></tr";

        public override string GetDesignTimeHtml()
        {
            // Make the full extent of the control more visible in the designer.
            // If the border style is None or NotSet, change the border to
            // a wide, blue, dashed line. Include the caption within the border.
            MyFormView myGV = (MyFormView)Component;
            string markup = null;
            int charX;

            // Check if the border style should be changed.
            if (myGV.BorderStyle == BorderStyle.NotSet ||
                myGV.BorderStyle == BorderStyle.None)
            {
                BorderStyle oldBorderStyle = myGV.BorderStyle;
                Unit oldBorderWidth = myGV.BorderWidth;
                Color oldBorderColor = myGV.BorderColor;

                // Set the design-time properties and catch any exceptions.
                try
                {
                    myGV.BorderStyle = BorderStyle.Dashed;
                    myGV.BorderWidth = Unit.Pixel(3);
                    myGV.BorderColor = Color.Blue;

                    // Call the base method to generate the markup.
                    markup = base.GetDesignTimeHtml();
                }
                catch (Exception ex)
                {
                    markup = GetErrorDesignTimeHtml(ex);
                }
                finally
                {
                    // Restore the properties to their original settings.
                    myGV.BorderStyle = oldBorderStyle;
                    myGV.BorderWidth = oldBorderWidth;
                    myGV.BorderColor = oldBorderColor;
                }
            }
            else
                // Call the base method to generate the markup.
                markup = base.GetDesignTimeHtml();

            // Look for a <caption> tag.
            if ((charX = markup.IndexOf(capTag)) > 0)
            {
                // Replace the first caption with 
                // "tr><td colspan=9 align=center".
                // It is okay if the colspan exceeds the 
                // number of columns in the table.
                markup = markup.Remove(charX,
                    capTag.Length).Insert(charX, trOpen);

                // Replace the second caption with "td></tr".
                if ((charX = markup.IndexOf(capTag, charX)) > 0)
                    markup = markup.Remove(charX,
                        capTag.Length).Insert(charX, trClose);
            }
            return markup;

        } // GetDesignTimeHtml
    } // MyFormViewDesigner
} // Examples.CS.WebControls.Design

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 98, Windows 2000 SP4, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0
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