【发布时间】：2011-12-03 03:07:39
【问题描述】：
我在网格视图中填充下拉列表时遇到了困难。 我使用以下代码创建了列：
If Not Me.GridViewIsConstructed Then
gv.Columns.Add(createComboBoxWithDDL(Me.ddlGPField.Items, "Bank_GP_Field_Name", "GPField"))
gv.Columns.Add(createComboBoxWithDDL(Me.ddlBankField.Items, "Bank_Bank_Field_Name", "BankField"))
End IF
Private Function createComboBoxWithDDL(ByVal obj As Object, ByVal nDataFieldName As String, ByVal nColName As String) As DataGridViewComboBoxColumn
Dim combo As New DataGridViewComboBoxColumn
combo.DataSource = obj
combo.DataPropertyName = nDataFieldName
combo.Name = nColName
Return combo
End Function
问题是我无法获得格式化句柄来用我需要的索引填充组合框。这是我对 BankField 下拉列表的代码尝试。
If e.ColumnIndex = gv.Columns("BankField").Index Then
e.FormattingApplied = True
Dim _row = gv.Rows(e.RowIndex)
Dim _cell As New DataGridViewComboBoxColumn
fillGPFieldList(_cell)
_cell.DisplayIndex = 1
_cell.DisplayMember = "Credit"
_cell.ValueMember = "Credit"
_cell.DataSource = _cell.Items
e.Value = _cell
End If
If e.ColumnIndex = gv.Columns("TrxType").Index Then
e.FormattingApplied = True
e.Value = "BAL"
End If
Gridview 可以很好地显示下拉对象，它总是设置为索引 -1。
请帮忙
V***********附录编辑***********V
很遗憾，没有人回答我的问题。所以我解决了整个问题。它很难看，如果有任何反馈，我将不胜感激。
我永远无法让 ComboBox 绑定到数据源。我尝试了一切，直到我变蓝。所以我去了基础知识并编码了所有自动的东西。我很好奇为什么自动绑定不起作用。也许是因为我的 gridview 数据源是 LINQ。
这就是我如何做到的。我希望有人能从我最后 48 小时的 delima 中受益：
首先，要知道我的表单上有两个下拉列表，一个是 GPField，另一个是 BankField。这些已填充的静态 DDL。所以我用它们来欺骗值而不是使用枚举。
我不认为这很重要，但这是我填写 GPField 和 BankField 的方式：
Sub fillGPFieldListDDL(ByVal obj As Object)
Dim db As New CompanyDataDataContext
Dim myConn As New Connection With {.ConnCls = ConnCls}
myConn.dbConnect(db)
'Setup the GP Field list
obj.Items.Clear()
For Each fld In db.getGPFieldList(Me.ddlImportID.SelectedItem, ddlImportTypes.BNKREC_IMPORTS_WORK)
obj.Items.Add(fld.Trim)
Next
db.Connection.Close()
db.Connection.Dispose()
db.Dispose()
End Sub
Sub fillBankFieldListDDL(ByVal obj As Object)
If String.IsNullOrEmpty(ddlImportID.Text) Then
Return
End If
Dim db As New CompanyDataDataContext
Dim myConn As New Connection With {.ConnCls = ConnCls}
myConn.dbConnect(db)
'Setup the Bank Field list
obj.Items.Clear()
For Each fld In db.getImportIDVirtualFields(Me.ddlImportID.Text, ddlImportTypes.BNKREC_IMPORTS_WORK)
obj.Items.Add(fld.Trim)
Next
db.Connection.Close()
db.Connection.Dispose()
db.Dispose()
End Sub
接下来，根据用户的选择，我使用以下函数填充我的网格：
Function fillToleranceFieldsGridView(ByVal nTrxType As String) As Integer
Dim myConn As New Connection With {.ConnCls = ConnCls}
Try
Using db As New CompanyDataDataContext
myConn.dbConnect(db)
'Dim _query As IEnumerable(Of TWO_Tolerance_Field) = (From tf In db.getToleranceSetupRecordFields(nTrxType, BankToleranceRecordTypes.MasterRecord) _
' Select tf)
'Dim _query2 As IEnumerable(Of TWO_Tolerance_Field) = db.getToleranceSetupRecordFields(nTrxType, BankToleranceRecordTypes.MasterRecord)
Dim _query3 = (From t In db.TWO_Tolerance_Fields _
Where t.TRXTYPESTRING = nTrxType And t.RCRDTYPE = BankToleranceRecordTypes.MasterRecord _
Select t.Bank_Bank_Field_Number, t.Bank_GP_Field_Name, t.TRXTYPESTRING)
Dim gv = Me.DataGridViewX1
gv.AutoGenerateColumns = False
gv.AllowUserToAddRows = False
gv.AllowUserToDeleteRows = False
gv.AllowUserToResizeRows = False
gv.AutoSize = True
gv.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.AllCells
'gv.DataSource = _query3
If Not Me.GridViewIsConstructed Then
'Add in the combo box for GPField Names
Dim _comboCol As DataGridViewComboBoxColumn
_comboCol = CreateComboBoxColumn(Me.ddlGPField.Items, _
ColumnNameData.Bank_GP_Field_Name.ToString, _
FieldNames.GPField.ToString)
gv.Columns.Add(_comboCol)
_comboCol = CreateComboBoxColumn(Me.ddlBankField.Items, _
ColumnNameData.Bank_Bank_Field_Number.ToString, _
FieldNames.BankField.ToString)
gv.Columns.Add(_comboCol)
Dim col As DataGridViewColumn = _
New DataGridViewTextBoxColumn()
Dim _cell = New DataGridViewTextBoxCell
Dim _coll = New DataGridViewColumn(_cell)
Dim _colIndex As Integer = 0
''Bind to an existing column Left in for easy access for a simple text box
'_coll = New DataGridViewColumn(_cell)
'_coll.Name = ColumnNameData.Bank_GP_Field_Name.ToString
'_coll.ReadOnly = True
'_coll.HeaderText = ColumnNameData.Bank_GP_Field_Name.ToString
'_colIndex = gv.Columns.Add(_coll)
'gv.Columns(_colIndex).DataPropertyName = ColumnNameData.Bank_GP_Field_Name.ToString
Me.GridViewIsConstructed = True
End If
gv.Rows.Clear()
Dim ri As Integer = 0
For Each r In _query3
Dim _row As New DataGridViewRow
_row.CreateCells(gv)
_row.Cells(FieldNames.GPField).Value = r.Bank_GP_Field_Name.ToString.Trim
_row.Cells(FieldNames.BankField).Value = ddlBankField.Items(r.Bank_Bank_Field_Number - 1).ToString.Trim
gv.Rows.Add(_row)
ri += 1
Next
db.Connection.Close()
db.Connection.Dispose()
End Using
Return 0
Catch ex As Exception
Throw ex
Finally
myConn.Dispose()
End Try
End Function
因此，未回答的问题是： 1）。我不能使用 _query 或 _query2 作为 gridview 的数据源，但 _query3 确实适用于简单的文本框。 2）。如果使用 _query3 作为 gv.datasource，为什么我的组合框会在执行 gv.Columns.Add(_comboCol) 时抛出 "bank_gp_field_name" not found 错误 3）。我理解我无法将 gv 绑定到 _query3 的原因，因为 Bank_Bank_field_number 中的数据是整数，而 DDL 值在整数和字符串值之间没有转换。但是我注释掉了期望 GPField 在标准绑定上运行的字段。我仍然得到“名为“Bank_GP_Field_Name”的字段在 gv.Columns.Add(_comboCol) 上不存在
所以，总结一下，为什么下面的代码不起作用而上面的代码起作用？
Function fillToleranceFieldsGridView(ByVal nTrxType As String) As Integer
Dim myConn As New Connection With {.ConnCls = ConnCls}
Try
Using db As New CompanyDataDataContext
myConn.dbConnect(db)
'Dim _query As IEnumerable(Of TWO_Tolerance_Field) = (From tf In db.getToleranceSetupRecordFields(nTrxType, BankToleranceRecordTypes.MasterRecord) _
' Select tf)
'Dim _query2 As IEnumerable(Of TWO_Tolerance_Field) = db.getToleranceSetupRecordFields(nTrxType, BankToleranceRecordTypes.MasterRecord)
Dim _query3 = (From t In db.TWO_Tolerance_Fields _
Where t.TRXTYPESTRING = nTrxType And t.RCRDTYPE = BankToleranceRecordTypes.MasterRecord _
Select t.Bank_Bank_Field_Number, t.Bank_GP_Field_Name, t.TRXTYPESTRING)
Dim gv = Me.DataGridViewX1
gv.AutoGenerateColumns = False
gv.AllowUserToAddRows = False
gv.AllowUserToDeleteRows = False
gv.AllowUserToResizeRows = False
gv.AutoSize = True
gv.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.AllCells
gv.DataSource = _query3
If Not Me.GridViewIsConstructed Then
'Add in the combo box for GPField Names
Dim _comboCol As DataGridViewComboBoxColumn
_comboCol = CreateComboBoxColumn(Me.ddlGPField.Items, _
ColumnNameData.Bank_GP_Field_Name.ToString, _
FieldNames.GPField.ToString)
gv.Columns.Add(_comboCol)
'_comboCol = CreateComboBoxColumn(Me.ddlBankField.Items, _
' ColumnNameData.Bank_Bank_Field_Number.ToString, _
' FieldNames.BankField.ToString)
'gv.Columns.Add(_comboCol)
Dim col As DataGridViewColumn = _
New DataGridViewTextBoxColumn()
Dim _cell = New DataGridViewTextBoxCell
Dim _coll = New DataGridViewColumn(_cell)
Dim _colIndex As Integer = 0
''Bind to an existing column Left in for easy access for a simple text box
'_coll = New DataGridViewColumn(_cell)
'_coll.Name = ColumnNameData.Bank_GP_Field_Name.ToString
'_coll.ReadOnly = True
'_coll.HeaderText = ColumnNameData.Bank_GP_Field_Name.ToString
'_colIndex = gv.Columns.Add(_coll)
'gv.Columns(_colIndex).DataPropertyName = ColumnNameData.Bank_GP_Field_Name.ToString
Me.GridViewIsConstructed = True
End If
'gv.Rows.Clear()
'Dim ri As Integer = 0
'For Each r In _query3
' Dim _row As New DataGridViewRow
' _row.CreateCells(gv)
' _row.Cells(FieldNames.GPField).Value = r.Bank_GP_Field_Name.ToString.Trim
' _row.Cells(FieldNames.BankField).Value = ddlBankField.Items(r.Bank_Bank_Field_Number - 1).ToString.Trim
' gv.Rows.Add(_row)
' ri += 1
'Next
db.Connection.Close()
db.Connection.Dispose()
End Using
Return 0
Catch ex As Exception
Throw ex
Finally
myConn.Dispose()
End Try
End Function
Private Function CreateComboBoxColumn(ByVal obj As ComboBox.ObjectCollection, ByVal nDataFieldName As String, ByVal nColName As String) _
As DataGridViewComboBoxColumn
Dim column As New DataGridViewComboBoxColumn()
With (column)
.HeaderText = nColName
.DropDownWidth = 160
.Width = 90
.MaxDropDownItems = 3
.FlatStyle = FlatStyle.Flat
.DataSource = obj
.DataPropertyName = nDataFieldName
.Name = nColName
.ValueMember = nDataFieldName
.DisplayMember = .ValueMember
End With
Return column
End Function
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标签： vb.net winforms datagridview drop-down-menu