仅当我之前运行另一个子时，显示 DataGridView 的代码才有效

Question

我编写了一个代码来将某个 DataTable 的内容显示/隐藏到 DataGridView 中。

当我单击按钮时，DataGridView 会出现和消失。 我没有收到错误，但没有显示任何内容。

但是，如果我单击另一个按钮（显示另一个表单）然后返回主表单，则代码可以正常工作。 (??!!??)

我无法理解是什么（在第二个代码中）使第一个代码起作用：似乎两个代码之间没有联系。

编辑
我做了一些测试，我可以添加更多信息：
我添加了一个按钮来显示（在 msgbox 中）DataGridView 属性。 控件已正确添加，所有属性均正确。 属性“Visible”设置为“True”，但 DataGridView 仍然“不可见”。

我添加了一个按钮来设置DGV_Tbl.Visible = False 和DGV_Tbl.Visible = True 当我单击它时，会出现 DataGridView。

但如果我再次单击 Btn_ShowHideTbl（删除 DGV）并再次单击（重新添加 DGV）DataGridView 仍然“不可见”。

当我单击按钮打开第二个表单然后关闭它以返回到第一个表单时，不会发生这种情况。
在这种情况下，一切正常。

我可以解决将DGV_Tbl.Visible = False 和DGV_Tbl.Visible = True 添加到第一个代码的问题，但我认为这不是一个好主意。
我想了解问题并在没有“奇怪指令”的情况下解决它。

编辑 2
我注意到代码 .AutoResizeColumns(DataGridViewAutoSizeColumnsMode.AllCells) 在不打开第二种形式的情况下也不起作用。
在这个指令上DGV_Tbl.Visible = False 和DGV_Tbl.Visible = True 没有效果。

编辑 3
我已经按照接受的答案做了，但我发布了另一个问题here，希望了解我的代码有什么问题。

这是我显示/隐藏 DataGridView 的代码：

Private Sub Btn_ShowHideTbl_Click(sender As Object, e As EventArgs) Handles Btn_ShowHideTbl.Click
    ShowHideTbl()
End Sub

Private Sub ShowHideTbl()
    'Look for DGV
    Dim DGV_Tbl As DataGridView = Nothing
    Try
        DGV_Tbl = CType(Me.Controls("DGV_Tbl"), DataGridView)
    Catch ex As Exception
        MsgBox(ex.ToString)
    End Try
    Try
       'If not found I need to show data
       If DGV_Tbl Is Nothing Then
            If Me.CBox_ProcType.Text = "Select a Procedure" Then
                MsgBox("You need To select a Procedure", vbInformation, "Unable to show table")
                Exit Sub
            End If
            DGV_Tbl = New DataGridView
            'It needs to copy data to another DataTable to show Double as Currency
            Using DTemp As DataTable = New DataTable
                Dim TblName As String = Me.CBox_ProcType.Text
                For C As Integer = 0 To DS_All.Tables(TblName).Columns.Count - 1
                    DTemp.Columns.Add(DS_All.Tables(TblName).Columns(C).ColumnName, Type.GetType("System.String"))
                Next
                Dim Arr(DS_All.Tables(TblName).Columns.Count - 1) As String
                For R As Integer = 0 To DS_All.Tables(TblName).Rows.Count - 1
                    For C As Integer = 0 To DS_All.Tables(TblName).Columns.Count - 1
                        If C = 0 Then
                            Arr(C) = DS_All.Tables(TblName).Rows(R)(C).ToString
                        Else
                            Arr(C) = FormatCurrency(DS_All.Tables(TblName).Rows(R)(C).ToString, 2)
                        End If
                    Next
                    DTemp.Rows.Add(Arr)
                Next
                'Working on created DataGridView
                With DGV_Tbl
                    .Name = "DGV_Tbl"
                    'Add control to the Form
                    Me.Controls.Add(DGV_Tbl)
                    .DataSource = DTemp
                    .AutoResizeColumns(DataGridViewAutoSizeColumnsMode.AllCells)
                    .RowHeadersVisible = False
                    .AllowUserToAddRows = False
                    .AllowUserToDeleteRows = False
                End With
            'Dispose the copied DataTable
            End Using
            'Resizing Form to include new DataGridView
            Dim DGV_H As Integer = 0
            Dim DGV_W As Integer = 0
            For Each R As DataGridViewRow In DGV_Tbl.Rows
                DGV_H += R.Height
            Next
            DGV_H += DGV_Tbl.ColumnHeadersHeight
            'Add more space to include spaces between cells
            DGV_H += CInt(DGV_Tbl.Rows.Count * 0.45)
            For Each C As DataGridViewColumn In DGV_Tbl.Columns
                DGV_W += C.Width
            Next
            'Add more space to include spaces between cells
            DGV_W += CInt(DGV_Tbl.Columns.Count * 0.45)
            DGV_Tbl.Height = DGV_H
            DGV_Tbl.Width = DGV_W
            'Resize the Form
            Me.Height += DGV_H + 30
            Me.Controls("DGV_Tbl").Location = New Point(15, Me.Height - DGV_H - 30)
            'Align for currency
            For x As Integer = 1 To DGV_Tbl.Columns.Count - 1
                DGV_Tbl.Columns(x).DefaultCellStyle.Alignment = DataGridViewContentAlignment.MiddleRight
            Next
        Else
            'If DGV exists I need to remove it and resize the form
            Dim DGV_H As Integer = DGV_Tbl.Height
            DGV_Tbl.Dispose()
            Me.Height -= (DGV_H + 30)
        End If
    Catch ex As Exception
        MsgBox(ex.ToString)
    End Try
End Sub

这是显示另一个表单的按钮中的代码（以及关闭表单并返回的代码）：

Private Sub Btn_ShowSummary_Click(sender As Object, e As EventArgs) Handles Btn_ShowSummary.Click
    Try
        If Me.CBox_ProcType.Text = "Select a Procedure" OrElse Me.CBox_ProcValue.Text = "Select a Value" Then
            MsgBox("It needs to select a Procedure and a Value",
                   vbInformation, "Unable to show table")
            Exit Sub
        End If

        Summary = "...Here Some text..." & vbCrLf & Split(Me.CBox_ProcType.Text, ".")(1).Trim & vbCrLf & vbCrLf
        Summary &= "...Here Some text..." & Me.CBox_ProcValue.Text & vbCrLf & vbCrLf
        Dim C1Wdt% = -50 
        Dim C2Wdt% = TBox_TotAll.Text.Length 
        For R As Integer = 1 To 4
            Dim CBox_Phase As CheckBox = CType(Me.TLP_Phases.Controls("CBox_Phase" & R.ToString), CheckBox)
            Dim TBox_ValPh As TextBox = CType(Me.TLP_Phases.Controls("TBox_ValPh" & R.ToString), TextBox)
            If CBox_Phase.Checked Then
                Summary &= String.Format("{0," & C1Wdt.ToString & "} {1," & C2Wdt.ToString & "}",
                                         CBox_Phase.Text, TBox_ValPh.Text) & vbCrLf
                Dim TBox_SelVarPh As TextBox = CType(Me.TLP_Phases.Controls("TBox_SelVarPh" & R.ToString), TextBox)
                If TBox_SelVarPh.Text = "" OrElse TBox_SelVarPh.Text = "€ 0,00" Then
                    Summary &= "...Here Some text..." & vbCrLf
                Else
                    Dim SelVarTxt$ = If(Val(TBox_SelVarPh.Text) > 0,
                        "...Here Some text..." & TBox_SelVarPh.Text,
                        "...Here Some text..." & TBox_SelVarPh.Text.Substring(1)) & vbCrLf
                    Summary &= SelVarTxt
                End If
            End If
        Next
        Summary &= String.Format("{0," & C1Wdt.ToString & "} {1," & C2Wdt.ToString & "}", "", New String(CChar("_"), C2Wdt)) & vbCrLf
        Summary &= String.Format("{0," & C1Wdt.ToString & "} {1," & C2Wdt.ToString & "}",
                                 "...Here Some text...",
                                 Me.TBox_TotPhases.Text) & vbCrLf
        If Me.TBox_PrtAdg.Text <> "€ 0,00" Then
            Summary &= String.Format("{0," & C1Wdt.ToString & "} {1," & C2Wdt.ToString & "}",
                                 "...Here Some text...",
                                 Me.TBox_PrtAdg.Text) & vbCrLf
            Summary &= "...Here Some text..." & TBox_PrtRapp.Text & "...Here Some text..." & TBox_CPrt.Text & "...Here Some text..." & vbCrLf
        End If
        Summary &= String.Format("{0," & C1Wdt.ToString & "} {1," & C2Wdt.ToString & "}",
                                 "...Here Some text..." & TBox_ForfPercent.Text,
                                 Me.TBox_ForfImp.Text) & vbCrLf
        Summary &= "...Here Some text..." & TBox_TotPhases.Text & ")" & vbCrLf
        Summary &= String.Format("{0," & C1Wdt.ToString & "} {1," & C2Wdt.ToString & "}", "", New String(CChar("_"), C2Wdt)) & vbCrLf
        Summary &= String.Format("{0," & C1Wdt.ToString & "} {1," & C2Wdt.ToString & "}",
                                 "...Here Some text...",
                                 Me.TBox_TotAll.Text) & vbCrLf
        Me.Hide()
        Me.ShowInTaskbar = False
        Frm_Summary.Show()
    Catch ex As Exception
        MsgBox(ex.ToString)
    End Try
End Sub

这里是返回按钮的代码：

Private Sub Btn_CloseNBack_Click(sender As Object, e As EventArgs) Handles Btn_CloseNBack.Click
    Frm_Base.ShowInTaskbar = True
    Frm_Base.Show()
    Me.Close()
End Sub

我没有看到代码之间有任何联系（但似乎我错了）请告诉我我缺少什么。

Answer 1

我可以为您的问题建议另一种方法吗？ 如果我是你，我会考虑使用绘制的 datagridview，事先将数据表内容放入其中。 然后在显示/隐藏按钮中，只需切换该 datagridview 的可见性以及重新计算表单大小。

对于货币列，您可以将数据表填充到datagridview中，然后将该列的格式设置为货币，而不是制作另一个表：

DGV_Tbl.Columns("CurrencyColumn").DefaultCellStyle.Format = "c"

关于datagridview列格式的更多信息可以找到here