为什么我会收到此错误？从字符串“Invoice”到类型“Integer”的转换无效答案

【问题标题】：Why am i getting this error ? Conversion from string "Invoice" to type 'Integer' is not valid为什么我会收到此错误？从字符串“Invoice”到类型“Integer”的转换无效
【发布时间】：2020-07-04 16:03:09
【问题描述】：

我正在尝试使用数据表从数据库中获取数据，然后将其传递到我的文本框中。这是我的代码。错误发生在我的第一行 me.txtInvoice.text。

    Try
        dtTable = MyBase.appMgr.fncTransactionSuccessful_Sel("1", strErrMsg)
        If strErrMsg = String.Empty Then
            If dtTable.Rows.Count > 0 Then
                Me.txtInvoiceNo.Text = dtTable("Invoice").ToString
                Me.txtAmountPaid.Text = "RM " & dtTable("Amount").ToString
                Me.txtPaymentDate.Text = dtTable("PaymentDate").ToString
                Me.txtPackageSelected.Text = dtTable("PackageSelected").ToString
                Me.txtPackageStartDate.Text = dtTable("PackageStartDate").ToString
                Me.txtPackageEndDate.Text = dtTable("PackageEndDate").ToString
            End If
    <div class="form-group col-lg-6 col-md-12 col-sm-6" style="margin-bottom: 0px; margin-top: 17px">
      <asp:TextBox ID="txtInvoiceNo" runat="server" Text="123466" CssClass="form-control"></asp:TextBox>
      </div>

【问题讨论】：

你是在尝试做dtTable.Rows(rowNum).Item("Invoice")吗？您不能直接从 DataTable 中选择字段（因为：哪一行？！）
第一行是否有标题，如“发票”、“金额”等，而不是值？

标签： asp.net database vb.net datatable

【解决方案1】：

也许你打算这样做：

    dtTable = MyBase.appMgr.fncTransactionSuccessful_Sel("1", strErrMsg)
    If strErrMsg = String.Empty Then
        If dtTable.Rows.Count > 0 Then

            Dim ro = dtTable(0) 'get the first row out of the table

            Me.txtInvoiceNo.Text = ro("Invoice").ToString
            Me.txtAmountPaid.Text = "RM " & ro("Amount").ToString
            Me.txtPaymentDate.Text = ro("PaymentDate").ToString
            Me.txtPackageSelected.Text = ro("PackageSelected").ToString
            Me.txtPackageStartDate.Text = ro("PackageStartDate").ToString
            Me.txtPackageEndDate.Text = ro("PackageEndDate").ToString
        End If

如果您使用强类型数据集，它会让您的生活更轻松。对于强类型表，此代码可能如下所示：

    dtTable = MyBase.appMgr.fncTransactionSuccessful_Sel("1", strErrMsg)
    If strErrMsg <> String.Empty Then 
        'do something here
        Return
    End If

    If dtTable.Count > 0 Then
        Dim ro = dtTable(0) 'get the first row out of the table

        Me.txtInvoiceNo.Text = ro.Invoice
        Me.txtAmountPaid.Text = "RM " & ro.Amount
        Me.txtPaymentDate.Text = ro.PaymentDate
        Me.txtPackageSelected.Text = ro.PackageSelected
        Me.txtPackageStartDate.Text = ro.PackageStartDate
        Me.txtPackageEndDate.Text = ro.PackageEndDate
    End If

意思是 Intellisense 可以帮助您处理列，因为它们是具有正确数据类型的正确属性

【讨论】：