Question

如何访问DataGridView中特定行的组合框的项集合？

我按如下方式填充组合：

          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

我希望能够为添加到网格的每个新行设置默认值，我还希望能够根据其他业务逻辑更改组合中的值。我意识到我可以直接设置单元格值，但我想避免将值硬编码到系统中并依赖数据库来填充。

我确信它必须是直截了当的，但这是在逃避我......

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。

您要创建一个从ComboBox继承并实现IDataGridViewEditingControl的新类（ComboEditingControl）：

（例如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

另外2个类，请注意在InitializeEditingControl中，您需要为您所在的特定行构建项目

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

最后在表单的OnLoad代码中，以编程方式将控件添加到Grid：

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

获得＆amp;设置只需使用ThisRow.Cells(ComboCol).Value

第一个字段是通用的，另一个字段继承并拥有您需要的每个DataGridView的自定义代码

HTH

Answer 2

您是否可以使用行索引直接在单元格中转换控件以访问当前行？

DataGridView组合框

2 个答案: