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FormViewDesigner.GetDesignTimeHtml 方法

  • 参考

定义

命名空间:
System.Web.UI.Design.WebControls
程序集:
System.Design.dll

获取用于在设计时呈现关联控件的标记。

public:
 override System::String ^ GetDesignTimeHtml();
public override string GetDesignTimeHtml ();
override this.GetDesignTimeHtml : unit -> string
Public Overrides Function GetDesignTimeHtml () As String

返回

String

一个 String，其中包含用于在设计时呈现 FormView 的标记。

示例

下面的代码示例演示如何重写 GetDesignTimeHtml 从 FormViewDesigner 类继承的 类中的 方法，以在设计时更改控件的外观 FormView 。 该示例在网格中添加一个新第一行，以包含 Caption 属性（如果 Caption 已定义）。 BorderStyle如果派生自 FormView 的控件的 属性是 NotSet 或 None 值，则会GetDesignTimeHtml在控件周围绘制蓝色虚线边框，使其范围更可见。 该示例不会更改控件的运行时外观。

// 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

' Generate the design-time markup.
Private Const capTag As String = "caption"
Private Const trOpen As String = "tr><td colspan=9 align=center"
Private Const trClose As String = "td></tr"

Public Overrides Function GetDesignTimeHtml() As String

    ' 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.
    Dim myGV As MyFormView = CType(Component, MyFormView)
    Dim markup As String = Nothing
    Dim charX As Integer

    ' Check if the border style should be changed.
    If (myGV.BorderStyle = BorderStyle.NotSet Or _
        myGV.BorderStyle = BorderStyle.None) Then

        Dim oldBorderStyle As BorderStyle = myGV.BorderStyle
        Dim oldBorderWidth As Unit = myGV.BorderWidth
        Dim oldBorderColor As Color = 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 = MyBase.GetDesignTimeHtml()

        Catch ex As Exception
            markup = GetErrorDesignTimeHtml(ex)

        Finally
            ' Restore the properties to their original settings.
            myGV.BorderStyle = oldBorderStyle
            myGV.BorderWidth = oldBorderWidth
            myGV.BorderColor = oldBorderColor
        End Try

    Else
        ' Call the base method to generate the markup.
        markup = MyBase.GetDesignTimeHtml()
    End If

    ' Look for a <caption> tag.
    charX = markup.IndexOf(capTag)
    If charX > 0 Then

        ' 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".
        charX = markup.IndexOf(capTag, charX)
        If charX > 0 Then
            markup = markup.Remove(charX, _
                capTag.Length).Insert(charX, trClose)
        End If
    End If

    Return markup

End Function ' GetDesignTimeHtml

注解

如果已为FormView控件定义了项模板，则如果无法获取数据源的架构，方法GetDesignTimeHtmlDataKeyNames会将控件的集合设置为空String数组。 刷新 GetDesignTimeHtmlTypeDescriptor 对象以强制调用 PreFilterProperties 方法。 GetDesignTimeHtml然后调用基方法以生成标记。

如果未为 FormView 控件定义项模板，则 GetDesignTimeHtml 调用 GetEmptyDesignTimeHtml 方法以生成呈现到占位符的标记。

继承者说明

如果重写 GetDesignTimeHtml() 方法，请务必调用基方法，因为它最终会通过多个重写级别调用 FormView 控件或控件的副本 FormView 来生成标记。

适用于

另请参阅