删除(进阶篇：服务器控件)

摘要
承上一篇文章「GridView+FormView 示范资料新增/修改/删除」，有人询问是否能简化程序代码；答案是可行的，方法就是由服务器控件下手。在此文章中，我们将扩充 GridView 及 FormView 控件，在 GridView 控件中新增 FormViewID 属性，关连至指定的 FormView 控件 ID，就可以轻易达到上篇文章中相同效果。

扩充 GridView 控件
首先我们继承 GridView 下来扩充功能，新增 FormViewID 属性，用来设定连结的 FormView 控件 ID。然后把原本在 GridView 的 RowCommand 事件中的程序代码，搬至 OnRowCommand 覆写方法中。
扩充功能的 TBGridView 控件完整程序代码如下，其中 OnLoad 方法中，会去判断 FormView 若为 TBFormView (扩充功能的 FormView)，会去设定其 GridView 属性。

Imports System
2

Imports System.Collections.Generic
3

Imports System.ComponentModel
4

Imports System.Text
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Imports System.Web
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Imports System.Web.UI
7

Imports System.Web.UI.WebControls
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Imports System.Drawing
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Namespace WebControls
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< _
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Description("TBGridView 控件"), _
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ToolboxData("<{0}:TBGridView runat=server></{0}:TBGridView>") _
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> _
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Public Class TBGridView
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Inherits GridView
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Private FFormViewID As String = String.Empty
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Private FFormView As FormView = Nothing
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''' <summary>
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''' 连结的 FormView 控件 ID。
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''' </summary>
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< _
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Description("连结的 FormView 控件 ID。"), _
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Themeable(False), _
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IDReferenceProperty(GetType(FormView)), _
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TypeConverter(GetType(TBFormViewIDConverter)), _
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Category("Data"), _
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DefaultValue("") _
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> _
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Public Property FormViewID() As String
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Get
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Return FFormViewID
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End Get
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Set(ByVal value As String)
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FFormViewID = value
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End Set
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End Property
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''' <summary>
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''' 连结的 FormView 控件。
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''' </summary>
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Protected Friend ReadOnly Property FormView() As FormView
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Get
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If String.IsNullOrEmpty(FFormViewID) Then Return Nothing
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If FFormView Is Nothing Then
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FFormView = CType(Me.Parent.FindControl(FFormViewID), FormView)
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End If
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Return FFormView
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End Get
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End Property
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''' <summary>
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''' 取得对应数据来源的数据列索引。
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''' </summary>
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''' <param name="RowIndex">GridView 的数据列索引。</param>
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Public Function GetDataRowIndex(ByVal RowIndex As Integer) As Integer
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Dim iRowIndex As Integer
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If Me.AllowPaging Then
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'GridView 有分页时，要把考虑目前的页数及每页笔数
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iRowIndex = Me.PageIndex * Me.PageSize + RowIndex
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Else
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'GridView 无分页时，直接使用 RowIndex
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iRowIndex = RowIndex
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End If
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Return iRowIndex
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End Function
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''' <summary>
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''' 覆写。引发 Load 事件。
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''' </summary>
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Protected Overrides Sub OnLoad(ByVal e As EventArgs)
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MyBase.OnLoad(e)
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If Me.FormView IsNot Nothing Then
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If TypeOf Me.FormView Is TBFormView Then
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DirectCast(Me.FormView, TBFormView).GridView = Me
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End If
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End If
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End Sub
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''' <summary>
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''' 覆写。引发 RowCommand 事件。
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''' </summary>
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Protected Overrides Sub OnRowCommand(ByVal e As GridViewCommandEventArgs)
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Dim iDataRowIndex As Integer
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Select Case e.CommandName.ToUpper
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Case "Edit".ToUpper '编辑模式
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If Me.FormView IsNot Nothing Then
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iDataRowIndex = GetDataRowIndex(CInt(e.CommandArgument))
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Me.FormView.PageIndex = iDataRowIndex
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Me.FormView.ChangeMode(FormViewMode.Edit) 'FormView 切换为编辑模式
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Me.FormView.Visible = True 'FormView 显示
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Me.Visible = False 'GridView 隐藏
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End If
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Case "Insert".ToUpper '新增模式
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If Me.FormView IsNot Nothing Then
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Me.FormView.ChangeMode(FormViewMode.Insert) 'FormView 切换为新增模式
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Me.FormView.Visible = True 'FormView 显示
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Me.Visible = False 'GridView 隐藏
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End If
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End Select
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MyBase.OnRowCommand(e)
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End Sub
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End Class
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End Namespace

扩充 FormView 控件
接下来继承 FormView 下来扩充功能，首先要新增一个 GridView 属性，当 TBGridView 有设定 FormViewID 时，且 FormView 的型别为 TBFormView 时，会去设定 TBFormView.GridView 属性，让 TBFormView 控件知道系结来源的 GridView，以做后序的相关程序控管。
TBFormView 的程序代码如下，一样把原本 FormView 相关事件的程序代码搬过来控件的程序代码中。

Imports System
2

Imports System.Collections.Generic
3

Imports System.ComponentModel
4

Imports System.Text
5

Imports System.Web
6

Imports System.Web.UI
7

Imports System.Web.UI.WebControls
8

Imports System.Drawing
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Imports Bee.Lib.TBLibFunc
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Namespace WebControls
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''' <summary>
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''' 利用使用者定义的样板，显示数据来源中单一数据录的值。支持编辑、删除及插入数据录。
14

''' </summary>
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< _
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Description("TBFormView 控件"), _
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ToolboxData("<{0}:TBFormView runat=server></{0}:TBFormView>") _
18

> _
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Public Class TBFormView
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Inherits FormView
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Private FGridView As GridView = Nothing
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''' <summary>
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''' 连结的 GridView 控件。
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''' </summary>
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Protected Friend Property GridView() As GridView
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Get
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Return FGridView
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End Get
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Set(ByVal value As GridView)
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FGridView = value
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End Set
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End Property
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''' <summary>
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''' 递归寻找指定 ID 的控件。
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''' </summary>
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''' <param name="Parent">父代控件。</param>
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''' <param name="CommandName">按钮命令名称。</param>
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''' <returns>回传 ID 符合的控件，若未找到则传回 Nothing。</returns>
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Private Overloads Function FindButtonControl(ByVal Parent As System.Web.UI.Control, ByVal CommandName As String) As IButtonControl
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Dim oControl As System.Web.UI.Control = Nothing
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Dim oButtonControl As IButtonControl = Nothing
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For Each oControl In Parent.Controls
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If (TypeOf oControl Is IButtonControl) Then
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oButtonControl = DirectCast(oControl, IButtonControl)
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If SameText(CommandName, oButtonControl.CommandName) Then
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Return oButtonControl
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End If
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Else
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If oControl.Controls.Count > 0 Then
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oButtonControl = FindButtonControl(oControl, CommandName)
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If oButtonControl IsNot Nothing Then
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Return oButtonControl
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End If
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End If
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End If
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Next
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Return Nothing
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End Function
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''' <summary>
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''' 依 CommandName 寻找对应的按钮。
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''' </summary>
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''' <param name="CommandName">按钮命令名称。</param>
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Private Overloads Function FindButtonControl(ByVal CommandName As String) As IButtonControl
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Return FindButtonControl(Me, CommandName)
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End Function
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''' <summary>
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''' 覆写。引发 Load 事件。
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''' </summary>
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Protected Overrides Sub OnLoad(ByVal e As EventArgs)
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'若预设为编辑模式，则将 InsertItemTemplate 设为 EditItemTemplate
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If Me.DefaultMode = FormViewMode.Edit Then
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Me.InsertItemTemplate = Me.EditItemTemplate
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End If
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MyBase.OnLoad(e)
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End Sub
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''' <summary>
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''' 覆写。引发 PreRender 事件。
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''' </summary>
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Protected Overrides Sub OnPreRender(ByVal e As EventArgs)
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Dim oButtonControl As IButtonControl
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MyBase.OnPreRender(e)
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If Me.Visible AndAlso Me.GridView IsNot Nothing Then
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Select Case Me.CurrentMode
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Case FormViewMode.Edit '编辑模式
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'隐藏新增钮
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oButtonControl = FindButtonControl("Insert")
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If oButtonControl IsNot Nothing Then
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DirectCast(oButtonControl, Control).Visible = False
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End If
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'显示更新钮
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oButtonControl = FindButtonControl("Update")
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If oButtonControl IsNot Nothing Then
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DirectCast(oButtonControl, Control).Visible = True
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End If
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Case FormViewMode.Insert
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'显示新增钮
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oButtonControl = FindButtonControl("Insert")
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If oButtonControl IsNot Nothing Then
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DirectCast(oButtonControl, Control).Visible = True
109

End If
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'隐藏更新钮
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oButtonControl = FindButtonControl("Update")
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If oButtonControl IsNot Nothing Then
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DirectCast(oButtonControl, Control).Visible = False
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End If
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End Select
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End If
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End Sub
118

119

''' <summary>
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''' 切换为浏览模式。
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''' </summary>
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Private Sub ChangeViewMode()
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Me.Visible = False
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Me.GridView.Visible = True
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Me.GridView.EditIndex = -1
126

End Sub
127

128

''' <summary>
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''' 覆写。引发 ItemInserted 事件。
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''' </summary>
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Protected Overrides Sub OnItemInserted(ByVal e As FormViewInsertedEventArgs)
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MyBase.OnItemInserted(e)
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'切换为浏览模式
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ChangeViewMode()
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End Sub
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137

''' <summary>
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''' 覆写。引发 ItemUpdated 事件。
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''' </summary>
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Protected Overrides Sub OnItemUpdated(ByVal e As FormViewUpdatedEventArgs)
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MyBase.OnItemUpdated(e)
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'切换为浏览模式
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ChangeViewMode()
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End Sub
145

146

''' <summary>
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''' 覆写。引发 ItemCommand 事件。
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''' </summary>
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Protected Overrides Sub OnItemCommand(ByVal e As FormViewCommandEventArgs)
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MyBase.OnItemCommand(e)
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End Sub
152

End Class
153

154

End Namespace

使用 TBGridView 及 TBFormView 控件
以上篇的范例程序做修改，只要将 aspx 中 GridView 置换为 TBGridView，而 FormView 置换为 TBFormView，并设定 TBGridView 的 FormViewID 属性为 TBFormView 控件 ID 即可。

<bee:TBGridView ID="GridView1" runat="server" AllowPaging="True" AutoGenerateColumns="False"

CellPadding="4" DataKeyNames="EmployeeID" DataSourceID="SqlDataSource1" EmptyDataText="沒有資料錄可顯示。"

ForeColor="#333333" GridLines="None" PageSize="5" FormViewID="FormView1">

而 aspx.vb 的程序代码可以简化如下，原本 GridView 及 FormView 相关操作的控管都可以省略掉。

Partial Class _Default
2

Inherits System.Web.UI.Page
3

Protected Sub GridView1_RowDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewRowEventArgs) Handles GridView1.RowDataBound
5

Dim oButton As Button
6

If e.Row.RowType = DataControlRowType.DataRow Then
8

'设定编辑钮的 CommandArgument
9

oButton = CType(e.Row.Cells(0).FindControl("btnEdit"), Button)
10

oButton.CommandArgument = e.Row.RowIndex.ToString
11

End If
12

End Sub
13

Protected Sub FormView1_PreRender(ByVal sender As Object, ByVal e As System.EventArgs) Handles FormView1.PreRender
15

Dim oFormView As FormView
16

Dim oTextBox As TextBox
17

oFormView = CType(sender, FormView)
19

If Not oFormView.Visible Then Exit Sub
20

Select Case oFormView.CurrentMode
22

Case FormViewMode.Edit '编辑模式
23

'显示 EmployeeID 的 TextBox
24

oTextBox = oFormView.FindControl("txtEmployeeID")
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oTextBox.Visible = False
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Case FormViewMode.Insert
27

'显示 EmployeeID 的 TextBox
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oTextBox = oFormView.FindControl("txtEmployeeID")
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oTextBox.Visible = True
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End Select
31

End Sub
32

End Class

后记
也许有人会问，可不可以连上述的程序代码都省略了，答案也是肯定的，只要去扩充 CommandField 及 TextBox 控件就可以达到零程序代码。对于 CommandField 的部分，要让 CommandField 的 Header 有辨法放「新增」钮；而 TextBox 的部分，要让 TextBox 有辨法自行判断所在的 FormView 的 CurrentMode，自行决定本身是否要显示或隐藏。

posted on 2008-05-12 16:47 jeff377 阅读(3682) 评论(3) 收藏举报

GridView+FormView 示范数据 新增/修改/删除(进阶篇：服务器控件)

GridView+FormView 示范数据新增/修改/删除(进阶篇：服务器控件)