DataGridView组合框

Question

如何访问DataGridView中特定行中组合框的项目集合？

我填充组合如下：

  Dim VATCombo As New DataGridViewComboBoxColumn 
      With VATCombo 
       .HeaderText = "VAT Rate" 
       .Name = .HeaderText 
       Dim VATCol As New JCVATRateCollection 

       VATCol.LoadAll(EntitySpaces.Interfaces.esSqlAccessType.StoredProcedure) 
       For Each Rate As JCVATRate In VATCol 
        .Items.Add(Rate.str.VATRate) 
       Next 
       .Sorted = True 

       VATCol = Nothing 

       .ToolTipText = "Select VAT Rate" 
       .AutoSizeMode = DataGridViewAutoSizeColumnMode.DisplayedCells 
       .CellTemplate.Style.BackColor = Color.Honeydew 
       .DisplayIndex = 8 
       .AutoSizeMode = DataGridViewAutoSizeColumnMode.Fill 

      End With 
      .Columns.Add(VATCombo) 
      VATCombo = Nothing 

我希望能够设置默认值为每个新行添加到网格中，我也希望能够改变值基于其他业务逻辑的组合。我意识到我可以直接设置单元格值，但我想避免将这些值硬编码到系统中，并依靠数据库来填充。

我敢肯定，它必须是直接的，但它躲避我.....

Answer 1

EditGridView中基本组合框的问题是所有行共享相同的组合框，因此您无法更改它。

您创建一个新的类（ComboEditingControl）从ComboBox和实施IDataGridViewEditingControl继承：

（如customdropdown.vb :)

Imports System.Collections.Generic 
Imports System.Drawing 
Imports System.Windows.Forms 

Friend Class ComboEditingControl 
Inherits ComboBox 
Implements IDataGridViewEditingControl 

Private dataGridViewControl As DataGridView 
Private valueIsChanged As Boolean = False 
Private rowIndexNum As Integer 
Private ItemSelected As String 

Public Sub New() 
    Me.DropDownStyle = ComboBoxStyle.DropDownList 
End Sub 


Public Property EditingControlFormattedValue() As Object _ 
    Implements IDataGridViewEditingControl.EditingControlFormattedValue 

    Get 
     Return ItemSelected 
    End Get 

    Set(ByVal value As Object) 
     If TypeOf value Is Decimal Then 
      Me.SelectedItem = value.ToString() 
     End If 
    End Set 
End Property 


Public Function GetEditingControlFormattedValue(ByVal context As DataGridViewDataErrorContexts) As Object _ 
    Implements IDataGridViewEditingControl.GetEditingControlFormattedValue 
    Return ItemSelected 
End Function 

Public ReadOnly Property EditingControlCursor() As Cursor _ 
    Implements IDataGridViewEditingControl.EditingPanelCursor 
    Get 
     Return MyBase.Cursor 
    End Get 
End Property 

Public Sub ApplyCellStyleToEditingControl(ByVal dataGridViewCellStyle As DataGridViewCellStyle) _ 
    Implements IDataGridViewEditingControl.ApplyCellStyleToEditingControl 

    Me.Font = dataGridViewCellStyle.Font 
    Me.ForeColor = dataGridViewCellStyle.ForeColor 
    Me.BackColor = dataGridViewCellStyle.BackColor 

End Sub 

Public Property EditingControlRowIndex() As Integer _ 
    Implements IDataGridViewEditingControl.EditingControlRowIndex 

    Get 
     Return rowIndexNum 
    End Get 
    Set(ByVal value As Integer) 
     rowIndexNum = value 
    End Set 

End Property 

Public Function EditingControlWantsInputKey(ByVal key As Keys, ByVal dataGridViewWantsInputKey As Boolean) As Boolean _ 
    Implements IDataGridViewEditingControl.EditingControlWantsInputKey 

    ' Let the DateTimePicker handle the keys listed. 
    Select Case key And Keys.KeyCode 
     Case Keys.Up, Keys.Down, Keys.Home, Keys.End, Keys.PageDown, Keys.PageUp 
      Return True 
     Case Else 
      Return False 
    End Select 
End Function 

Public Sub PrepareEditingControlForEdit(ByVal selectAll As Boolean) _ 
    Implements IDataGridViewEditingControl.PrepareEditingControlForEdit 
    ' No preparation needs to be done. 
End Sub 

Public ReadOnly Property RepositionEditingControlOnValueChange() As Boolean Implements _ 
    IDataGridViewEditingControl.RepositionEditingControlOnValueChange 
    Get 
     Return False 
    End Get 
End Property 

Public Property EditingControlDataGridView() As DataGridView _ 
    Implements IDataGridViewEditingControl.EditingControlDataGridView 

    Get 
     Return dataGridViewControl 
    End Get 
    Set(ByVal value As DataGridView) 
     dataGridViewControl = value 
    End Set 

End Property 

Public Property EditingControlValueChanged() As Boolean _ 
    Implements IDataGridViewEditingControl.EditingControlValueChanged 

    Get 
     Return valueIsChanged 
    End Get 
    Set(ByVal value As Boolean) 
     valueIsChanged = value 
    End Set 
End Property 


''' <summary> 
''' Notify the DataGridView that the contents of the cell have changed. 
''' </summary> 
''' <param name="eventargs"></param> 
''' <remarks></remarks> 
Protected Overrides Sub OnSelectedIndexChanged(ByVal eventargs As EventArgs) 
    valueIsChanged = True 
    dataGridViewControl.NotifyCurrentCellDirty(True) 
    MyBase.OnSelectedItemChanged(eventargs) 
    ItemSelected = SelectedItem.ToString() 
End Sub 
End Class 

---

2个班，记下InitializeEditingControl您需要为您所在的特定行建立物品

Friend Class ComboColumn 
    Inherits DataGridViewColumn 

    Public Sub New() 
     MyBase.New(New ComboCell()) 
    End Sub 

    Public Overrides Property CellTemplate() As DataGridViewCell 
     Get 
      Return MyBase.CellTemplate 
     End Get 
     Set(ByVal value As DataGridViewCell) 
      ' Ensure that the cell used for the template is a ComboCell. 
      If Not (value Is Nothing) AndAlso Not value.GetType().IsAssignableFrom(GetType(ComboCell)) Then 
       Throw New InvalidCastException("Must be a ComboCell") 
      End If 
      MyBase.CellTemplate = value 
     End Set 
    End Property 
End Class 

Friend Class ComboCell 
    Inherits DataGridViewTextBoxCell 

    Public Sub New() 
    End Sub 

    Public Overrides Sub InitializeEditingControl(ByVal rowIndex As Integer, ByVal initialFormattedValue As Object, ByVal dataGridViewCellStyle As DataGridViewCellStyle) 
     ' Set the value of the editing control to the current cell value. 
     MyBase.InitializeEditingControl(rowIndex, initialFormattedValue, dataGridViewCellStyle) 

     Dim ctl As ComboEditingControl = CType(DataGridView.EditingControl, ComboEditingControl) 

     Dim GetValueFromRowToUseForBuildingCombo As String = Me.DataGridView.Rows(rowIndex).Cells(0).Value.ToString() 

     ctl.Items.Clear() 
     For Each thing As String In ACollection 
      ctl.Items.Add(Sheet) 
     Next 


     If Me.Value Is Nothing Then 
      ctl.SelectedIndex = -1 
     Else 
      ctl.SelectedItem = Me.Value 
     End If 
    End Sub 

    Public Overrides ReadOnly Property EditType() As Type 
     Get 
      Return GetType(ComboEditingControl) 
     End Get 
    End Property 

    Public Overrides ReadOnly Property ValueType() As Type 
     Get 
      Return GetType(String) 
     End Get 
    End Property 

    Public Overrides ReadOnly Property FormattedValueType() As System.Type 
     Get 
      Return GetType(String) 
     End Get 
    End Property 

    Public Overrides ReadOnly Property DefaultNewRowValue() As Object 
     Get 
      Return "" 
     End Get 
    End Property 
End Class 

终于在窗体的onload代码，编程控件添加到网格：

Dim c As New ComboColumn 
c.HeaderText = "Sheet" 
c.DataPropertyName = "My Combo" 
c.ToolTipText = "Select something from my combo" 
MyDataGridView.Columns.Add(c) 

至获取&设置只使用ThisRow.Cells(ComboCol).Value

第一个字段是通用的，其他的继承和有为每个需要

HTH

Answer 2

莫非你不能直接转换使用行索引来访问当前行的单元格内的控制？