ASP.NET使用Visual Basic语言更新GridView中显示的sql数据

Question

ASP.NET Visual Basic 我正在尝试更新 GridView 中显示的已连接 SQL 表的数据。但我的 Visual Basic 代码在 GridView 中找不到 VRMModel-TextBox。我可以在GridView中看到数据。我单击更新数据，它找到 RowIndex，但找不到 TextBox 或 GridView-Control。它将 VRMModel 和 ComponentDefect 的值响应为 NOTHING。这是我的代码：

Protected Sub GridView1_RowUpdating(ByVal sender As Object, ByVal e As GridViewUpdateEventArgs)
    Dim row As GridViewRow = GridView1.Rows(e.RowIndex)
    Dim VRMModel As TextBox = CType(row.FindControl("VRMModel"), TextBox)
    Dim ComponentDefect As TextBox = CType(row.FindControl("ComponentDefect"), TextBox)
    Dim connectionString As String = ConfigurationManager.ConnectionStrings("VRM_Test").ConnectionString
    Using connection As New SqlConnection(connectionString)
        Using command As New SqlCommand("UPDATE tblVRMModel SET VRMModel = @VRMModel, ComponentDefect = @ComponentDefect ", connection)
            command.Parameters.AddWithValue("@VRMModel", VRMModel)
            command.Parameters.AddWithValue("@ComponentDefect", ComponentDefect)
            connection.Open()
            command.ExecuteNonQuery()
        End Using
    End Using
    GridView1.EditIndex = -1
    BindGrid()
End Sub

这里缺少什么？

我认为问题发生在以下部分：

    Dim VRMModel As TextBox = CType(row.FindControl("VRMModel"), TextBox)
    Dim ComponentDefect As TextBox = CType(row.FindControl("ComponentDefect"), TextBox)

它没有找到任何控件（GridView 的单元格）将其声明为 TextBox 来获取其值。

Answer 1

为什么不考虑在 GV 底部放置一个保存按钮，然后允许用户自由切换和编辑任何行（就像在 Excel 中，甚至在桌面数据网格中一样）。因此，用户可以跳来跳去、跳来跳去并对所有行进行更改，然后我们就有一个保存按钮。

上面不仅呈现了一种用于编辑的常见 UI 类型，而且还省去了复杂的 UI，也省去了 GridView 的大量复杂代码和技巧事件。只需转储所有 GridView 事件，并编写一些干净且易于阅读的代码即可。

因此，说出这个标记：

        <style>
            .borderhide input {
                border: none;
                background-color: transparent
            }

            .borderhide textarea {
                border: none;
                background-color: transparent
            }
        </style>


        <asp:GridView ID="GridView1" runat="server"
            AutoGenerateColumns="False" 
            DataKeyNames="ID"
            CssClass="table table-hover borderhide" Width="50%">
            <Columns>
                <asp:TemplateField HeaderText="First"><ItemTemplate>
                    <asp:TextBox ID="txtFirst" runat="server" Text='<%#Eval("FirstName") %>' >
                    </asp:TextBox>
                </ItemTemplate></asp:TemplateField>
                <asp:TemplateField HeaderText="Last"><ItemTemplate>
                    <asp:TextBox ID="txtLast" runat="server" Text='<%#Eval("LastName") %>' >
                    </asp:TextBox>
                </ItemTemplate></asp:TemplateField>
                <asp:TemplateField HeaderText="HotelName"><ItemTemplate>
                    <asp:TextBox ID="txtHotel" runat="server" Text='<%#Eval("HotelName") %>' >
                    </asp:TextBox>
                </ItemTemplate></asp:TemplateField>
                <asp:TemplateField HeaderText="Description">
                    <ItemTemplate>
                        <asp:TextBox ID="txtDescription"
                            runat="server" TextMode="MultiLine"
                            Text='<%# Eval("Description") %>'
                            Height="60px" Width="330px">
                        </asp:TextBox>
                    </ItemTemplate>
                </asp:TemplateField>
            </Columns>
        </asp:GridView>
        <br />
        <asp:Button ID="cmdSave" runat="server" Text="Save/Done"
            CssClass="btn btn-dark"
            OnClick="cmdSave_Click" />

我们背后的代码也相当简单。

Dim rstHotels As New DataTable
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

    If Not IsPostBack Then
        LoadData()
        Session("rstHotels") = rstHotels
    Else
        rstHotels = Session("rstHotels")
    End If

End Sub


Sub LoadData()

    Dim strSQL =
        "SELECT * FROM tblHotelsA
        WHERE Active = 1
        ORDER BY HotelName"

    rstHotels = MyRst(strSQL)
    GridView1.DataSource = rstHotels
    GridView1.DataBind()

End Sub

Sub GridToTable()

    ' send grid rows back to persisted table

    For Each gRow As GridViewRow In GridView1.Rows
        If gRow.RowType = DataControlRowType.DataRow Then

            Dim OneRow As DataRow = rstHotels.Rows(gRow.DataItemIndex)
            OneRow("FirstName") = DirectCast(gRow.FindControl("txtFirst"), TextBox).Text
            OneRow("LastName") = DirectCast(gRow.FindControl("txtLast"), TextBox).Text
            OneRow("HotelName") = DirectCast(gRow.FindControl("txtHotel"), TextBox).Text
            OneRow("Description") = DirectCast(gRow.FindControl("txtDescription"), TextBox).Text

        End If
    Next

End Sub

Protected Sub cmdSave_Click(sender As Object, e As EventArgs)

    GridToTable()
    Using conn As New SqlConnection(My.Settings.TEST4)
        Using cmdSQL As New SqlCommand("SELECT * FROM tblHotelsA", conn)

            Dim da As New SqlDataAdapter(cmdSQL)
            Dim daU As New SqlCommandBuilder(da)

            conn.Open()
            da.Update(rstHotels)

        End Using
    End Using

    ' at this point all changes saved to database
    ' we no doubt at this point will navagate to another page.
    'Response.Redirect("Some other page.aspx")

End Sub

所以，最终结果是这样的：

因此，用户可以进行切换、进行更改。然后我们有一个保存按钮，而且我们也只有一个保存操作，用于将结果发送回数据库。