Question

尝试从下拉列表输入我的值并从GridViewRow输入值时，我一直收到上述错误。

它还说“标准表达式中的数据类型不匹配”，我从列表/行中提取问题和论文的ID，并将它们输入到我的数据库中。

以下是显示错误的代码。

Using con As New OleDb.OleDbConnection(ConfigurationManager.ConnectionStrings.Item("ConnectionString").ConnectionString)
    con.Open()
    Dim allCheckedRows = From row In CreateTest.Rows.Cast(Of GridViewRow)()
                 Let chkQuestion = DirectCast(row.FindControl("QuestionSelector"), CheckBox)
                 Where chkQuestion.Checked
                 Select row
    For Each checkedRow As GridViewRow In allCheckedRows

        Dim QuestionID As String = (checkedRow.Cells(0).Text)

        Dim PaperID As String = DropDownList1.SelectedValue

        Dim insertExamQuery = "INSERT INTO QuestionInPaper VALUES ('QuestionID', 'PaperID');"

        Dim insertExamCmd = con.CreateCommand()
        insertExamCmd.CommandText = insertExamQuery
        insertExamCmd.ExecuteNonQuery()

    Next
End Using

这是aspx所有这些都指的是：

<asp:GridView ID="CreateTest" runat="server" 
        AllowSorting="True" AutoGenerateColumns="False" CellPadding="4" 
        DataKeyNames="QuestionID" DataSourceID="SqlDataSource1" ForeColor="#333333" 
        GridLines="None">
    <AlternatingRowStyle BackColor="White" ForeColor="#284775" />
    <Columns>
        <asp:TemplateField HeaderText="Select">
            <ItemTemplate>
                <asp:CheckBox ID="QuestionSelector" runat="server" />
            </ItemTemplate>
        </asp:TemplateField>
        <asp:BoundField DataField="QuestionID" HeaderText="QuestionID" 
            InsertVisible="False" ReadOnly="True" SortExpression="QuestionID" />
        <asp:BoundField DataField="Answer" HeaderText="Answer" 
            SortExpression="Answer" />
        <asp:BoundField DataField="Question" HeaderText="Question" 
            SortExpression="Question" />
        <asp:BoundField DataField="SubjectID" HeaderText="SubjectID" 
            SortExpression="SubjectID" />
        <asp:TemplateField></asp:TemplateField>
    </Columns>
    <asp:SqlDataSource ID="SqlDataSource1" runat="server" 
        ConnectionString="<%$ ConnectionStrings:ConnectionString %>" 
        ProviderName="<%$ ConnectionStrings:ConnectionString.ProviderName %>" 
        SelectCommand="SELECT [QuestionID], [Answer], [Question], [SubjectID] FROM [Question]">
    </asp:SqlDataSource>

    <asp:DropDownList ID="DropDownList1" runat="server" 
        DataSourceID="SqlDataSource3" DataTextField="PaperID" DataValueField="PaperID">
    </asp:DropDownList>

你能看到这种不匹配的地方吗？非常感谢。

Answer 1

您说在QuestionInPaper中的两个字段都是数字类型，但您正在尝试插入字符串数据 - “QuestionID”和“PaperID”。您需要将它们作为参数添加到命令中。您也将它们创建为String，代码和数据库中的两种类型应该相等。

    Using con As New OleDb.OleDbConnection(ConfigurationManager.ConnectionStrings.Item("ConnectionString").ConnectionString)
        con.Open()
        Dim allCheckedRows = From row In CreateTest.Rows.Cast(Of GridViewRow)()
                     Let chkQuestion = DirectCast(row.FindControl("QuestionSelector"), CheckBox)
                     Where chkQuestion.Checked
                     Select row
        For Each checkedRow As GridViewRow In allCheckedRows

            '// change type and parse
            Dim QuestionID As Decimal = Decimal.Parse(checkedRow.Cells(0).Text)
            Dim PaperID As Decimal = Decimal.Parse(DropDownList1.SelectedValue)

            '// changed
            Dim insertExamQuery = "INSERT INTO QuestionInPaper (QuestionID, PaperID) VALUES (?, ?);"

            Dim insertExamCmd = con.CreateCommand()

            '// added below
            insertExamCmd.Parameters.Add("@QuestionID", OleDb.OleDbType.Numeric).Value = QuestionID
            insertExamCmd.Parameters.Add("@PaperID", OleDb.OleDbType.Numeric).Value = PaperID
            '// end add

            insertExamCmd.CommandText = insertExamQuery
            insertExamCmd.ExecuteNonQuery()

        Next
    End Using

用户代码未处理OlEdB异常

1 个答案: