无需链接按钮即可编辑的 DataGrid

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引言

本文档介绍了如何创建一个可编辑的 ASP.NET DataGrid。

使用代码

这是一个名为 EditGrid 的虚拟目录的 Web 应用程序。您可以使用 VS.NET 2003 创建相同的虚拟目录，或者创建任何其他虚拟目录并将路径映射到此目录，以便从浏览器访问它。由于我使用了 Access 2002 作为我的数据库，您需要在您的机器上安装 MS Access。

此应用程序的重要部分

1. 带有 TextBox 和 DataGrid 作为项目模板的 DataGrid，以启用编辑，以及两个按钮，一个用于向网格添加新行，另一个用于将网格数据保存到数据库。

   <table class="TABLE_MAIN_NEW" width="100%" ID="Table1">
   <!--tab 3 Starts-->
     <tr vAlign="top">
      <td colSpan="4"></td>
      <td align="right"><asp:button id="btnAdd" runat="server" 
          CausesValidation="False" Text="Add" Width="91px" Height="22"
          CssClass="BUTTON_MEDIUM"></asp:button>
      </td>
     </tr>
     <tr vAlign="top">
      <td align="center" colSpan="5">
       <div class="dgrStyle_new">
       <asp:datagrid id="dgEditGrid" runat="server" 
          CssClass="DGR_MAIN" AutoGenerateColumns="False" width="100%">
            <AlternatingItemStyle CssClass="DGR_ALTERNATE"></AlternatingItemStyle>
            <ItemStyle CssClass="DGR_ITEM"></ItemStyle>
            <HeaderStyle CssClass="DGR_HEADER"></HeaderStyle>
            <Columns>
               <asp:TemplateColumn HeaderText="Description">
                <ItemTemplate>
                  <asp:TextBox MaxLength="50" runat="server" 
                      ID="txtDESCRIPTION" cssclass="TEXTBOX_MEDIUM_DG1" 
                      Text='<%#Container.DataItem("DESCRIPTION")%>' />
                </ItemTemplate>
               </asp:TemplateColumn>
               <asp:TemplateColumn HeaderText="Drop Down">
                <ItemTemplate>
                 <asp:DropDownList id="ddlDrop" runat="server" 
                  Width="100px" cssclass="DROPDOWN_SMALL_DG"></asp:DropDownList>
                </ItemTemplate>
               </asp:TemplateColumn>
               <asp:BoundColumn DataField="itemNumber" HeaderText="Item_No" 
                                         Visible="False"></asp:BoundColumn>
            </Columns>
       </asp:datagrid>
       </div>
      </td>
     </tr>
     <tr vAlign="top">
      <td colSpan="4"></td>
      <td align="right">
         <asp:button id="btnSave" runat="server" 
            CausesValidation="False" Text="Save" Width="91px" Height="22"
            CssClass="BUTTON_MEDIUM">
         </asp:button>
      </td>
     </tr>
   </table>

2. 用于将数据从数据库加载到 DataSet 的加载例程。

   Private Sub LoadFile()
   
       Dim con As OleDbConnection
       Dim dtaAdapter As OleDbDataAdapter
       Dim dstCopy As New DataSet
   
       Try
           Dim strPath As String = Server.MapPath("Data") & "\Auto.mdb"
   
           con = New System.Data.OleDb.OleDbConnection("provider=" & _ 
                 "Microsoft.Jet.OLEDB.4.0; " & "data source=" & strPath)
           dtaAdapter = New OleDbDataAdapter("Select * from Table1", con)
           dtaAdapter.Fill(dstCopy, "tbl_Temp_Data")
           con.Close()
           Session.Add("TempData", dstCopy)
           dgEditGrid.DataSource = dstCopy.Tables(0)
           dgEditGrid.DataBind()
   
       Catch ex As Exception
               Throw ex
       End Try
   End Sub

3. 用于将数据从 DataSet 加载到网格的 BindDrop 例程。

   Private Sub BindDrop()
       If Not IsNothing(Session("TempData")) Then
           dstTempData = Session("TempData")
           If Not IsNothing(dstTempData.Tables(0)) _
                   AndAlso dstTempData.Tables(0).Rows.Count > 0 Then
               dgEditGrid.DataSource = dstTempData.Tables(0)
               dgEditGrid.DataBind()
           End If
       End If
   End Sub

4. 添加按钮 Click 事件，用于向 DataSet 添加新行，从而向网格添加新行。

   Private Sub btnAdd_Click(ByVal sender As Object, _
                    ByVal e As System.EventArgs) Handles btnAdd.Click
       Try
   
           If Not IsNothing(Session("TempData")) Then
               dstTempData = Session("TempData")
               Dim drwRow As DataRow
               Dim intPreRow As Integer
               intPreRow = dstTempData.Tables(0).Rows.Count
               '///////////////
   
               Dim dgItem As DataGridItem
               For Each dgItem In dgEditGrid.Items
                   Dim intRow As Integer = dgItem.ItemIndex
                   If intRow <> -1 Then
   
                       Dim txtDescription As TextBox = _
                         CType(dgItem.Cells(0).FindControl("txtDESCRIPTION"), _
                         TextBox)
                       Dim ddlDGDrop As DropDownList = _
                         CType(dgItem.Cells(1).FindControl("ddlDrop"), _
                         DropDownList)
                       dstTempData.Tables(0).Rows(intRow)("DESCRIPTION")_
                                                    = txtDescription.Text
                       dstTempData.Tables(0).Rows(intRow)("Type")_
                                         = ddlDGDrop.SelectedValue
   
                   End If
               Next
   
               '//////////////
   
               Dim intFinalRow As Integer
               drwRow = dstTempData.Tables(0).NewRow()
               dstTempData.Tables(0).Rows.Add(drwRow)
               intFinalRow = dstTempData.Tables(0).Rows.Count - 1
   
               dstTempData.Tables(0).Rows(intFinalRow)("DESCRIPTION") = ""
               dstTempData.Tables(0).Rows(intFinalRow)("Type") = ""
               Session("TempData") = dstTempData
               BindDrop()
   
           End If
   
       Catch objException As Exception
           Finally
       End Try
   End Sub

5. 保存按钮 Click 事件，用于将数据从网格保存到数据库。

   Private Sub btnSave_Click(ByVal sender As Object, _
               ByVal e As System.EventArgs) Handles btnSave.Click
       Dim con As OleDbConnection
       Dim dtaAdapter As OleDbDataAdapter
       Dim dstCopy As New DataSet
       Dim cmdGrid As OleDbCommand
       Dim strQuery As String
   
       Dim intError As Integer = 0
       Dim strPath As String = Server.MapPath("Data") & "\Auto.mdb"
   
       con = New System.Data.OleDb.OleDbConnection("provider" & _
             "=Microsoft.Jet.OLEDB.4.0; " & "data source=" & strPath)
       con.Open()
       Dim dgItem As DataGridItem
       For Each dgItem In dgEditGrid.Items
           Dim txtDesc As TextBox = _
             CType(dgItem.Cells(0).FindControl("txtDESCRIPTION"), TextBox)
           Dim ddlType As DropDownList = _
             CType(dgItem.Cells(1).FindControl("ddlDrop"), DropDownList)
           Dim item As Integer
           If txtDesc.Text.Trim <> String.Empty And _
                   ddlType.SelectedItem.Text <> "-Select-" Then
               If IsNumeric(dgItem.Cells(2).Text) Then
                   item = CInt(dgItem.Cells(2).Text)
                   strQuery = "Update Table1 SET DESCRIPTION='" + txtDesc.Text _
                              + "',TYPE='" + ddlType.SelectedItem.Text + _
                              "' WHERE itemNumber=" + CStr(item)
               Else
                   item = 0
                   strQuery = "INSERT INTO Table1(DESCRIPTION,TYPE) VALUES('" _
                              + txtDesc.Text + "','" + _
                              ddlType.SelectedItem.Text + "')"
               End If
               cmdGrid = New OleDbCommand(strQuery, con)
               cmdGrid.ExecuteNonQuery()
               strQuery = String.Empty
               cmdGrid.Dispose()
           End If
       Next
   
       con.Close()
       LoadFile()
   End Sub

6. 用于填充下拉列表数据的 BindListControls 例程。

   Private Sub BindListControls(ByRef ddlDrop As DropDownList)
       Dim lstType As ListItem
       lstType = New ListItem("-Select-", "-Select-")
       ddlDrop.Items.Insert(0, lstType)
       lstType = New ListItem("Car", "Car")
       ddlDrop.Items.Insert(1, lstType)
       lstType = New ListItem("Bus", "Bus")
       ddlDrop.Items.Insert(2, lstType)
       lstType = New ListItem("Truck", "Truck")
       ddlDrop.Items.Insert(3, lstType)
       lstType = New ListItem("Bike", "Bike")
       ddlDrop.Items.Insert(4, lstType)
   End Sub

7. 用于填充下拉列表的 DataGrid ItemDataBound 事件。

   Private Sub dgEditGrid_ItemDataBound(ByVal sender As Object, _
             ByVal e As System.Web.UI.WebControls.DataGridItemEventArgs) _
             Handles dgEditGrid.ItemDataBound
       Try
           If e.Item.ItemType = ListItemType.Item Or e.Item.ItemType_
                                  = ListItemType.AlternatingItem Then
               Dim intRow As Integer = e.Item.ItemIndex
               If intRow = -1 Then
                   Exit Sub
               End If
               If Not IsNothing(Session("TempData")) Then
   
                   dstTempData = Session("TempData")
                   Dim CurrentDrop As String = _
                       dstTempData.Tables(0).Rows(intRow)("Type")
                   Dim itemSub As ListItem
                   Dim ddlDGDrop As DropDownList = _
                     CType(e.Item.Cells(1).FindControl("ddlDrop"), DropDownList)
                   BindListControls(ddlDGDrop)
                   itemSub = ddlDGDrop.Items.FindByText(CurrentDrop)
                   If Not itemSub Is Nothing Then itemSub.Selected = True
               End If
           End If
       Catch objException As Exception
           Finally
       End Try
   End Sub

关注点

我在将 Lotus Notes 应用程序转换为 Windows 时发现了这种方法。