例外：从字符串“<text>”到“Integer”类型的转换无效

Question

编辑：我有一段代码曾经几乎应该工作，突然间它开始抛出一个dbnull异常（之前没有）。现在，多亏了@david sdot，我得到了程序中的着色代码。

这是工作着色代码

    Private Sub Button6_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button6.Click

    'If Not IsNothing(DataGridView2.Rows("As (Arsen)")) Then

    'Kategorier i kolonner (vanlig)
    'As
    Dim UL1As As Double = 8
    Dim UL2As As Double = 20
    Dim UL3As As Double = 50
    Dim Ul4As As Double = 600
    Dim Ul5As As Double = 1000

    If Me.DataGridView2.CurrentRow.Cells(0).Value Is DBNull.Value Then
        MessageBox.Show("Cellen er tom.")
    Else

        For i As Integer = 0 To Me.DataGridView2.Rows.Count - 1
            If Me.DataGridView2.Rows(i).Cells("As (Arsen)").Value < UL1As Then
                Me.DataGridView2.Rows(i).Cells("As (Arsen)").Style.BackColor = Color.DodgerBlue
            ElseIf Me.DataGridView2.Rows(i).Cells("As (Arsen)").Value >= UL1As And Me.DataGridView2.Rows(i).Cells("As (Arsen)").Value < UL2As Then
                Me.DataGridView2.Rows(i).Cells("As (Arsen)").Style.BackColor = Color.LawnGreen
            ElseIf Me.DataGridView2.Rows(i).Cells("As (Arsen)").Value >= UL2As And Me.DataGridView2.Rows(i).Cells("As (Arsen)").Value < UL3As Then
                Me.DataGridView2.Rows(i).Cells("As (Arsen)").Style.BackColor = Color.Yellow
            ElseIf Me.DataGridView2.Rows(i).Cells("As (Arsen)").Value >= UL3As And Me.DataGridView2.Rows(i).Cells("As (Arsen)").Value < Ul4As Then
                Me.DataGridView2.Rows(i).Cells("As (Arsen)").Style.BackColor = Color.Orange
            ElseIf Me.DataGridView2.Rows(i).Cells("As (Arsen)").Value >= Ul4As And Me.DataGridView2.Rows(i).Cells("As (Arsen)").Value < Ul5As Then
                Me.DataGridView2.Rows(i).Cells("As (Arsen)").Style.BackColor = Color.Red
            ElseIf Me.DataGridView2.Rows(i).Cells("As (Arsen)").Value >= Ul5As Then
                Me.DataGridView2.Rows(i).Cells("As (Arsen)").Style.BackColor = Color.BlueViolet
            End If
        Next
         End If
     End Sub

结果如下：

我也想用彩色导出到Excel，但我无法使用相同的逻辑来处理导出代码。

Private Sub ExportToExcel()
    ' Creating a Excel object.
    Dim excel As Microsoft.Office.Interop.Excel._Application = New Microsoft.Office.Interop.Excel.Application()
    Dim workbook As Microsoft.Office.Interop.Excel._Workbook = excel.Workbooks.Add(Type.Missing)
    Dim worksheet As Microsoft.Office.Interop.Excel._Worksheet = Nothing

    Try

        worksheet = workbook.ActiveSheet

        worksheet.Name = "ExportedFromDatGrid"

        Dim cellRowIndex As Integer = 1
        Dim cellColumnIndex As Integer = 1


        'Loop through each row and read value from each column.
        For i As Integer = 0 To DataGridView2.Rows.Count - 2
            For j As Integer = 0 To DataGridView2.Columns.Count - 1
                ' Excel index starts from 1,1. As first Row would have the Column headers, adding a condition check.
                If cellRowIndex = 1 Then
                    worksheet.Cells(cellRowIndex, cellColumnIndex) = DataGridView2.Columns(j).HeaderText
                Else
                    worksheet.Cells(cellRowIndex, cellColumnIndex) = DataGridView2.Rows(i).Cells(j).Value
                End If
                cellColumnIndex += 1
            Next
            cellColumnIndex = 1
            cellRowIndex += 1
        Next

        If Not IsNothing(DataGridView2.Rows("As (Arsen)")) Then

            'As
            Dim UL1As As Double = 8
            Dim UL2As As Double = 20
            Dim UL3As As Double = 50
            Dim Ul4As As Double = 600
            Dim Ul5As As Double = 1000

            'Gir nå feilmeldingen 'Conversion from string "As (Arsen)" to type 'Integer' is not valid'

            For i As Integer = 0 To DataGridView2.Rows.Count - 2
                'For j As Integer = 0 To DataGridView2.Columns.Count - 1
                If DataGridView2.Rows(i).Cells("As (Arsen)").Value < UL1As Then
                    worksheet.Cells(i).Interior.Color = System.Drawing.ColorTranslator.ToOle(System.Drawing.Color.DodgerBlue)
                ElseIf DataGridView2.Rows(i).Cells("As (Arsen)").Value >= UL1As And Me.DataGridView2.Rows(i).Cells("As (Arsen)").Value < UL2As Then
                    worksheet.Cells(i).Interior.Color = System.Drawing.ColorTranslator.ToOle(System.Drawing.Color.LawnGreen)
                ElseIf DataGridView2.Rows(i).Cells("As (Arsen)").Value >= UL2As And Me.DataGridView2.Rows(i).Cells("As (Arsen)").Value < UL3As Then
                    worksheet.Cells(i).Interior.Color = System.Drawing.ColorTranslator.ToOle(System.Drawing.Color.Yellow)
                ElseIf DataGridView2.Rows(i).Cells("As (Arsen)").Value >= UL3As And Me.DataGridView2.Rows(i).Cells("As (Arsen)").Value < Ul4As Then
                    worksheet.Cells(i).Interior.Color = System.Drawing.ColorTranslator.ToOle(System.Drawing.Color.Orange)
                ElseIf DataGridView2.Rows(i).Cells("As (Arsen)").Value >= Ul4As And Me.DataGridView2.Rows(i).Cells("As (Arsen)").Value < Ul5As Then
                    worksheet.Cells(i).Interior.Color = System.Drawing.ColorTranslator.ToOle(System.Drawing.Color.Red)
                ElseIf DataGridView2.Rows(i).Cells("As (Arsen)").Value >= Ul5As Then
                    worksheet.Cells(i).Interior.Color = System.Drawing.ColorTranslator.ToOle(System.Drawing.Color.BlueViolet)
                End If
                'cellColumnIndex += 1
                'Next
                cellColumnIndex = 1
                cellRowIndex += 1
            Next


        Else
            MessageBox.Show("Cellen er tom")
            Exit Sub
        End If
        'Getting the location And file name of the excel to save from user.
        Dim saveDialog As New SaveFileDialog()
        saveDialog.Filter = "Excel files (*.xlsx)|*.xlsx|All files (*.*)|*.*"
        saveDialog.FilterIndex = 2

        If saveDialog.ShowDialog() = System.Windows.Forms.DialogResult.OK Then
            workbook.SaveAs(saveDialog.FileName)
            MessageBox.Show("Export Successful")
        End If
    Catch ex As System.Exception
        MessageBox.Show(ex.Message)
    Finally
        excel.Quit()
        workbook = Nothing
        excel = Nothing
    End Try

End Sub

想法，有人吗？

Answer 1

你的问题在这里：

Me.DataGridView2.Rows(i).Cells("As (Arsen)").Value

单元格期望整数作为索引（如.Cells（1））。并且由于错误状态As (Arsen)无法转换为整数。

因此，要么您知道Cells索引，要么您必须在第一行中查找它才能找到它。

Answer 2

此代码解决了问题：

            'As
        Dim UL1As As Double = 8
        Dim UL2As As Double = 20
        Dim UL3As As Double = 50
        Dim Ul4As As Double = 600
        Dim Ul5As As Double = 1000

        For i As Integer = 0 To DataGridView2.Rows.Count - 2
            For j As Integer = 2 To 2
                If DataGridView2.Rows(i).Cells("As (Arsen)").Value < UL1As Then
                    worksheet.Cells(i + 1, j + 1).Interior.Color = System.Drawing.ColorTranslator.ToOle(System.Drawing.Color.DodgerBlue)
                ElseIf DataGridView2.Rows(i).Cells("As (Arsen)").Value >= UL1As And Me.DataGridView2.Rows(i).Cells("As (Arsen)").Value < UL2As Then
                    worksheet.Cells(i + 1, j + 1).Interior.Color = System.Drawing.ColorTranslator.ToOle(System.Drawing.Color.LawnGreen)
                ElseIf DataGridView2.Rows(i).Cells("As (Arsen)").Value >= UL2As And Me.DataGridView2.Rows(i).Cells("As (Arsen)").Value < UL3As Then
                    worksheet.Cells(i + 1, j + 1).Interior.Color = System.Drawing.ColorTranslator.ToOle(System.Drawing.Color.Yellow)
                ElseIf DataGridView2.Rows(i).Cells("As (Arsen)").Value >= UL3As And Me.DataGridView2.Rows(i).Cells("As (Arsen)").Value < Ul4As Then
                    worksheet.Cells(i + 1, j + 1).Interior.Color = System.Drawing.ColorTranslator.ToOle(System.Drawing.Color.Orange)
                ElseIf DataGridView2.Rows(i).Cells("As (Arsen)").Value >= Ul4As And Me.DataGridView2.Rows(i).Cells("As (Arsen)").Value < Ul5As Then
                    worksheet.Cells(i + 1, j + 1).Interior.Color = System.Drawing.ColorTranslator.ToOle(System.Drawing.Color.Red)
                ElseIf DataGridView2.Rows(i).Cells("As (Arsen)").Value >= Ul5As Then
                    worksheet.Cells(i + 1, j + 1).Interior.Color = System.Drawing.ColorTranslator.ToOle(System.Drawing.Color.BlueViolet)
                End If
                cellColumnIndex += 1
            Next
            cellColumnIndex = 1
            cellRowIndex += 1
        Next

我不得不对j索引进行硬编码以将格式应用于正确的行。讨厌，但它是一个工作的地方。

现在我只需要找出如何在不删除第一个数据行的情况下导出标题行...