Question

我有1个datagridview 3列

Column1 = StartLoading
Column2 = FinishLoading
Column3 = TotalLoadingHours

如果用户在StartLoading和FinishLoading Columns中输入日期和时间，则从TotalLoadingHours列开始显示从开始到结束的总小时数。

我的问题是，如果用户仅在StartLoading Column中输入日期和时间，则总会出现错误 - ＆＃34;字符串未被识别为有效的DateTime＆＃34;。

感谢您的帮助。以下是我的代码。

Dim StartLoading As New System.DateTime
Dim FinishLoading As New System.DateTime

    For x As Integer = 0 To LoadingStatusDataGridview.Rows.Count - 2

        Dim StartLoadingvalue As String = LoadingStatusDataGridview.Rows(x).Cells(1).Value.ToString()
        StartLoading = DateTime.Parse(StartLoadingvalue)

        Dim FinishLoadingvalue As String = LoadingStatusDataGridview.Rows(x).Cells(2).Value.ToString()
        FinishLoading = DateTime.Parse(FinishLoadingvalue)

        Dim TotalLoadingHours1 As TimeSpan = (FinishLoading - StartLoading)

        String.Format("{0:00}:{1:00}:{2:00}", TotalLoadingHours1.TotalHours, TotalLoadingHours1.Minutes, TotalLoadingHours1.Seconds)

        Dim TotalLoadingHours2 As TimeSpan = (DateTime.Now - StartLoading)

        String.Format("{0:00}:{1:00}:{2:00}", TotalLoadingHours2.TotalHours, TotalLoadingHours2.Minutes, TotalLoadingHours2.Seconds)

        If IsDBNull(LoadingStatusDataGridview.Rows(x).Cells(1).Value()) OrElse LoadingStatusDataGridview.Rows(x).Cells(1).Value() Is Nothing Then
            LoadingStatusDataGridview.Rows(x).Cells(3).Value() = Nothing

        ElseIf IsDBNull(LoadingStatusDataGridview.Rows(x).Cells(2).Value()) OrElse LoadingStatusDataGridview.Rows(x).Cells(2).Value() Is Nothing Then
            LoadingStatusDataGridview.Rows(x).Cells(3).Value() = TotalLoadingHours2
        Else
            LoadingStatusDataGridview.Rows(x).Cells(3).Value() = TotalLoadingHours1
        End If

    Next

End Sub

Answer 1

尝试格式化单元格，如果FinishLoading或StartLoading为空，则不计算结果：

dataGridView1.Columns(0).DefaultCellStyle.Format = "MM/dd/yyyy"
dataGridView1.Columns(1).DefaultCellStyle.Format = "MM/dd/yyyy"

Answer 2

现在正在使用下面的代码..

    Dim startloading As New System.DateTime
    Dim finishloading As New System.DateTime

    For x As Integer = 0 To LoadingStatusDataGridview.Rows.Count - 2

        Dim startloadingvalue As String = LoadingStatusDataGridview.Rows(x).Cells(1).Value.ToString()

        If Not IsDBNull(LoadingStatusDataGridview.Rows(x).Cells(1).Value) AndAlso LoadingStatusDataGridview.Rows(x).Cells(1).Value.ToString.Length <> 0 Then
            startloading = DateTime.Parse(startloadingvalue)
        End If

        Dim finishloadingvalue As String = LoadingStatusDataGridview.Rows(x).Cells(2).Value.ToString()

        If Not IsDBNull(LoadingStatusDataGridview.Rows(x).Cells(2).Value) AndAlso LoadingStatusDataGridview.Rows(x).Cells(2).Value.ToString.Length <> 0 Then
            finishloading = DateTime.Parse(finishloadingvalue)
        End If

        If IsDBNull(LoadingStatusDataGridview.Rows(x).Cells(1).Value()) OrElse LoadingStatusDataGridview.Rows(x).Cells(1).Value() Is Nothing OrElse LoadingStatusDataGridview.Rows(x).Cells(1).Value.ToString.Trim() = "" Then
            LoadingStatusDataGridview.Rows(x).Cells(3).Value() = Nothing
        End If

        If IsDBNull(LoadingStatusDataGridview.Rows(x).Cells(2).Value()) OrElse LoadingStatusDataGridview.Rows(x).Cells(2).Value() Is Nothing OrElse LoadingStatusDataGridview.Rows(x).Cells(2).Value.ToString.Trim() = "" Then
            Dim LoadingHours2 As TimeSpan = (DateTime.Now - startloading)

            String.Format("{0:00}:{1:00}:{2:00}", LoadingHours2.TotalHours, LoadingHours2.Minutes, LoadingHours2.Seconds)

            LoadingStatusDataGridview.Rows(x).Cells(3).Value() = LoadingHours2
        Else
            Dim LoadingHours1 As TimeSpan = (finishloading - startloading)

            String.Format("{0:00}:{1:00}:{2:00}", LoadingHours1.TotalHours, LoadingHours1.Minutes, LoadingHours1.Seconds)

            LoadingStatusDataGridview.Rows(x).Cells(3).Value() = LoadingHours1
        End If

    Next

字符串未被识别

2 个答案: