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。
1Imports System
2Imports System.Collections.Generic
3Imports System.ComponentModel
4Imports System.Text
5Imports System.Web
6Imports System.Web.UI
7Imports System.Web.UI.WebControls
8Imports System.Drawing
9
10Namespace WebControlsNamespace WebControls
11 < _
12 Description("TBGridView 控件"), _
13 ToolboxData("<{0}:TBGridView runat=server></{0}:TBGridView>") _
14 > _
15 Public Class TBGridViewClass TBGridView
16 Inherits GridView
17 Private FFormViewID As String = String.Empty
18 Private FFormView As FormView = Nothing
19
20 /**/''' <summary>
21 ''' 连结的 FormView 控件 ID。
22 ''' </summary>
23 < _
24 Description("连结的 FormView 控件 ID。"), _
25 Themeable(False), _
26 IDReferenceProperty(GetType(FormView)), _
27 TypeConverter(GetType(TBFormViewIDConverter)), _
28 Category("Data"), _
29 DefaultValue("") _
30 > _
31 Public Property FormViewID()Property FormViewID() As String
32 Get
33 Return FFormViewID
34 End Get
35 Set(ByVal value As String)
36 FFormViewID = value
37 End Set
38 End Property
39
40 /**/''' <summary>
41 ''' 连结的 FormView 控件。
42 ''' </summary>
43 Protected Friend ReadOnly Property FormView()Property FormView() As FormView
44 Get
45 If String.IsNullOrEmpty(FFormViewID) Then Return Nothing
46 If FFormView Is Nothing Then
47 FFormView = CType(Me.Parent.FindControl(FFormViewID), FormView)
48 End If
49 Return FFormView
50 End Get
51 End Property
52
53 /**/''' <summary>
54 ''' 取得对应数据来源的数据列索引。
55 ''' </summary>
56 ''' <param name="RowIndex">GridView 的数据列索引。</param>
57 Public Function GetDataRowIndex()Function GetDataRowIndex(ByVal RowIndex As Integer) As Integer
58 Dim iRowIndex As Integer
59
60 If Me.AllowPaging Then
61 'GridView 有分页时，要把考虑目前的页数及每页笔数
62 iRowIndex = Me.PageIndex * Me.PageSize + RowIndex
63 Else
64 'GridView 无分页时，直接使用 RowIndex
65 iRowIndex = RowIndex
66 End If
67 Return iRowIndex
68 End Function
69
70 /**/''' <summary>
71 ''' 覆写。引发 Load 事件。
72 ''' </summary>
73 Protected Overrides Sub OnLoad()Sub OnLoad(ByVal e As EventArgs)
74 MyBase.OnLoad(e)
75 If Me.FormView IsNot Nothing Then
76 If TypeOf Me.FormView Is TBFormView Then
77 DirectCast(Me.FormView, TBFormView).GridView = Me
78 End If
79 End If
80 End Sub
81
82 /**/''' <summary>
83 ''' 覆写。引发 RowCommand 事件。
84 ''' </summary>
85 Protected Overrides Sub OnRowCommand()Sub OnRowCommand(ByVal e As GridViewCommandEventArgs)
86 Dim iDataRowIndex As Integer
87
88 Select Case e.CommandName.ToUpper
89 Case "Edit".ToUpper '编辑模式
90 If Me.FormView IsNot Nothing Then
91 iDataRowIndex = GetDataRowIndex(CInt(e.CommandArgument))
92 Me.FormView.PageIndex = iDataRowIndex
93 Me.FormView.ChangeMode(FormViewMode.Edit) 'FormView 切换为编辑模式
94 Me.FormView.Visible = True 'FormView 显示
95 Me.Visible = False 'GridView 隐藏
96 End If
97
98 Case "Insert".ToUpper '新增模式
99 If Me.FormView IsNot Nothing Then
100 Me.FormView.ChangeMode(FormViewMode.Insert) 'FormView 切换为新增模式
101 Me.FormView.Visible = True 'FormView 显示
102 Me.Visible = False 'GridView 隐藏
103 End If
104 End Select
105 MyBase.OnRowCommand(e)
106 End Sub
107
108 End Class
109End 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。
1Imports System
2Imports System.Collections.Generic
3Imports System.ComponentModel
4Imports System.Text
5Imports System.Web
6Imports System.Web.UI
7Imports System.Web.UI.WebControls
8Imports System.Drawing
9Imports Bee.Lib.TBLibFunc
10
11Namespace WebControlsNamespace WebControls
12 /**/''' <summary>
13 ''' 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>
15 < _
16 Description("TBFormView 控件"), _
17 ToolboxData("<{0}:TBFormView runat=server></{0}:TBFormView>") _
18 > _
19 Public Class TBFormViewClass TBFormView
20 Inherits FormView
21 Private FGridView As GridView = Nothing
22
23 /**/''' <summary>
24 ''' 连结的 GridView 控件。
25 ''' </summary>
26 Protected Friend Property GridView()Property GridView() As GridView
27 Get
28 Return FGridView
29 End Get
30 Set(ByVal value As GridView)
31 FGridView = value
32 End Set
33 End Property
34
35 /**/''' <summary>
36 ''' 递归寻找指定 ID 的控件。
37 ''' </summary>
38 ''' <param name="Parent">父代控件。</param>
39 ''' <param name="CommandName">按钮命令名称。</param>
40 ''' <returns>回传 ID 符合的控件，若未找到则传回 Nothing。</returns>
41 Private Overloads Function FindButtonControl()Function FindButtonControl(ByVal Parent As System.Web.UI.Control, ByVal CommandName As String) As IButtonControl
42 Dim oControl As System.Web.UI.Control = Nothing
43 Dim oButtonControl As IButtonControl = Nothing
44
45 For Each oControl In Parent.Controls
46 If (TypeOf oControl Is IButtonControl) Then
47 oButtonControl = DirectCast(oControl, IButtonControl)
48 If SameText(CommandName, oButtonControl.CommandName) Then
49 Return oButtonControl
50 End If
51 Else
52 If oControl.Controls.Count > 0 Then
53 oButtonControl = FindButtonControl(oControl, CommandName)
54 If oButtonControl IsNot Nothing Then
55 Return oButtonControl
56 End If
57 End If
58 End If
59 Next
60
61 Return Nothing
62 End Function
63
64 /**/''' <summary>
65 ''' 依 CommandName 寻找对应的按钮。
66 ''' </summary>
67 ''' <param name="CommandName">按钮命令名称。</param>
68 Private Overloads Function FindButtonControl()Function FindButtonControl(ByVal CommandName As String) As IButtonControl
69 Return FindButtonControl(Me, CommandName)
70 End Function
71
72 /**/''' <summary>
73 ''' 覆写。引发 Load 事件。
74 ''' </summary>
75 Protected Overrides Sub OnLoad()Sub OnLoad(ByVal e As EventArgs)
76 '若预设为编辑模式，则将 InsertItemTemplate 设为 EditItemTemplate
77 If Me.DefaultMode = FormViewMode.Edit Then
78 Me.InsertItemTemplate = Me.EditItemTemplate
79 End If
80 MyBase.OnLoad(e)
81 End Sub
82
83 /**/''' <summary>
84 ''' 覆写。引发 PreRender 事件。
85 ''' </summary>
86 Protected Overrides Sub OnPreRender()Sub OnPreRender(ByVal e As EventArgs)
87 Dim oButtonControl As IButtonControl
88
89 MyBase.OnPreRender(e)
90
91 If Me.Visible AndAlso Me.GridView IsNot Nothing Then
92 Select Case Me.CurrentMode
93 Case FormViewMode.Edit '编辑模式
94 '隐藏新增钮
95 oButtonControl = FindButtonControl("Insert")
96 If oButtonControl IsNot Nothing Then
97 DirectCast(oButtonControl, Control).Visible = False
98 End If
99 '显示更新钮
100 oButtonControl = FindButtonControl("Update")
101 If oButtonControl IsNot Nothing Then
102 DirectCast(oButtonControl, Control).Visible = True
103 End If
104 Case FormViewMode.Insert
105 '显示新增钮
106 oButtonControl = FindButtonControl("Insert")
107 If oButtonControl IsNot Nothing Then
108 DirectCast(oButtonControl, Control).Visible = True
109 End If
110 '隐藏更新钮
111 oButtonControl = FindButtonControl("Update")
112 If oButtonControl IsNot Nothing Then
113 DirectCast(oButtonControl, Control).Visible = False
114 End If
115 End Select
116 End If
117 End Sub
118
119 /**/''' <summary>
120 ''' 切换为浏览模式。
121 ''' </summary>
122 Private Sub ChangeViewMode()Sub ChangeViewMode()
123 Me.Visible = False
124 Me.GridView.Visible = True
125 Me.GridView.EditIndex = -1
126 End Sub
127
128 /**/''' <summary>
129 ''' 覆写。引发 ItemInserted 事件。
130 ''' </summary>
131 Protected Overrides Sub OnItemInserted()Sub OnItemInserted(ByVal e As FormViewInsertedEventArgs)
132 MyBase.OnItemInserted(e)
133 '切换为浏览模式
134 ChangeViewMode()
135 End Sub
136
137 /**/''' <summary>
138 ''' 覆写。引发 ItemUpdated 事件。
139 ''' </summary>
140 Protected Overrides Sub OnItemUpdated()Sub OnItemUpdated(ByVal e As FormViewUpdatedEventArgs)
141 MyBase.OnItemUpdated(e)
142 '切换为浏览模式
143 ChangeViewMode()
144 End Sub
145
146 /**/''' <summary>
147 ''' 覆写。引发 ItemCommand 事件。
148 ''' </summary>
149 Protected Overrides Sub OnItemCommand()Sub OnItemCommand(ByVal e As FormViewCommandEventArgs)
150 MyBase.OnItemCommand(e)
151 End Sub
152 End Class
153
154End 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。
1Partial Class _DefaultClass _Default
2 Inherits System.Web.UI.Page
3
4 Protected Sub GridView1_RowDataBound()Sub GridView1_RowDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewRowEventArgs) Handles GridView1.RowDataBound
5 Dim oButton As Button
6
7 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
14 Protected Sub FormView1_PreRender()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
18 oFormView = CType(sender, FormView)
19 If Not oFormView.Visible Then Exit Sub
20
21 Select Case oFormView.CurrentMode
22 Case FormViewMode.Edit '编辑模式
23 '显示 EmployeeID 的 TextBox
24 oTextBox = oFormView.FindControl("txtEmployeeID")
25 oTextBox.Visible = False
26 Case FormViewMode.Insert
27 '显示 EmployeeID 的 TextBox
28 oTextBox = oFormView.FindControl("txtEmployeeID")
29 oTextBox.Visible = True
30 End Select
31 End Sub
32End 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。
原文出处：
http://www.cnblogs.com/jeff377/
