Question

我在删除记录中遇到了一些问题。我使用VB.net和Access数据库。当我尝试运行此程序时没有错误，但记录没有在数据库中删除。有一个类要删除记录，这个类将调用另一个调用DeleteMultipleRecords的方法。这是我的代码，希望有人可以帮我解决这个问题。

-Default.aspx.vb -

Protected Sub btnDelete_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnDelete.Click
    'create string collection to store IDs of records to be deleted
    Dim idCollection As New StringCollection()
    Dim strID As String = String.Empty
    'Loop through GridView rows to find checked rows 
    For i As Integer = 0 To i < GridView1.Rows.Count - 1
        Dim chkDelete As CheckBox = DirectCast(GridView1.Rows(i).Cells(0).FindControl("chkSelect"), CheckBox)
        If chkDelete IsNot Nothing Then
            If chkDelete.Checked Then

                strID = GridView1.Rows(i).Cells(1).Text
                idCollection.Add(strID)

            End If
        End If
    Next

    'called method to delete record
    DeleteMultipleRecords(idCollection)

    'rebind(GridView)
    GridView1.DataBind()
End Sub
Private Sub DeleteMultipleRecords(ByVal idCollection As StringCollection)
    'create connection
    Dim cnnOLEDB As New OleDbConnection(strConnection)
    Dim IDs As String = ""

    'create string builder to store 
    'delete commands seperated by ;

    For Each id As String In idCollection

        IDs += id.ToString() & ","
    Next

    Try

        Dim strIDs As String = IDs.Substring(0, IDs.LastIndexOf(""))
        Dim strSql As String = ("Delete from Details WHERE ID = '" & strIDs & "' ")

        cmdOLEDB.CommandType = CommandType.Text
        cmdOLEDB.CommandText = strSql
        cmdOLEDB.Connection = cnnOLEDB
        cnnOLEDB.Open()
        cmdOLEDB.ExecuteNonQuery()
        cmdOLEDB.Dispose()

    Catch ex As OleDbException

        Dim errorMsg As String = "Error in Deletion"
        errorMsg += ex.Message
        Throw New Exception(errorMsg)

    Finally
        cnnOLEDB.Close()
    End Try

End Sub

-Default.aspx -

<asp:GridView ID="GridView1" runat="server" AllowPaging="True" 
        DataSourceID="SqlDataSource1" AutoGenerateColumns="False" DataKeyNames="ID">
        <Columns>
        <asp:TemplateField HeaderText="Select">
<ItemTemplate>

<asp:CheckBox ID="chkSelect" runat="server" />
</ItemTemplate>
 </asp:TemplateField>
<asp:BoundField DataField="ID" HeaderText="ID" SortExpression="ID"/>

<asp:TemplateField HeaderText="Name" 
                   SortExpression="Name">
<ItemTemplate>
<asp:TextBox ID="txtName" runat="server" 
             Text='<%# Bind("Name") %>'  ReadOnly="true" 
             BorderStyle="none" 
             BorderWidth="0px" >
</asp:TextBox>
</ItemTemplate>
</asp:TemplateField>

<asp:TemplateField HeaderText="Location" 
                   SortExpression="Location">
<ItemTemplate>
<asp:TextBox ID="txtLocation" runat="server" 
             Text='<%# Bind("Location") %>' 
             ReadOnly="true" 
             BorderStyle="none" BorderWidth="0px">
</asp:TextBox>
</ItemTemplate>
</asp:TemplateField>
        </Columns>
    </asp:GridView>

    <asp:SqlDataSource ID="SqlDataSource1" runat="server" 
        ConnectionString="<%$ ConnectionStrings:LabSystemDBConnectionString %>" 
        ProviderName="<%$ ConnectionStrings:LabSystemDBConnectionString.ProviderName %>" 
        SelectCommand="SELECT * FROM [Details]"
        DeleteCommand = "DELETE FROM [Details] WHERE ID = [@ID]">

    <DeleteParameters>
    <asp:Parameter Name="ID" />
    </DeleteParameters></asp:SqlDataSource>


    <asp:Button ID="btnDelete" runat="server" OnClick="btnDelete_Click" OnClientClick="return DeleteConfirmation();"  Text="Delete" />
    &nbsp;<br />

Answer 1

您应该更改这些行：

For Each id As String In idCollection

    IDs += "'" + id.ToString() & "',"
Next

Try

    Dim strIDs As String = IDs.Substring(0, IDs.LastIndexOf(""))
    Dim strSql As String = ("Delete from Details WHERE ID IN (" & strIDs & ")")

但是：此代码容易出错SQL INJECTION，您必须在2012年使用SQL参数。

Answer 2

请在

处设置一个断点

Dim strSql As String = ("Delete from Details WHERE ID IN (" & strIDs & ")")

然后运行你的应用程序，并将watch添加到strSql，当命中断点时，按F11，然后你可以看到strSql的内容，复制sql statment并在你的Access数据库中运行查询，看看它是不是工作

PS：尝试将[]添加到表名，DELETE FROM [Details]

使用GridView删除记录

2 个答案: