By default, the AdjustSearchColumn property is True. If the AdjustSearchColumn property is True, when the user hides a column using the Visible property, the SearchColumnIndex property gets a new value in order to point to a visible column. The SearchColumnIndex property indicates the column being displayed in the control's label area, when SingleEdit property is True.  Use the AdjustSearchColumn property to let the control to display a hidden column in the control's label area. 

For instance, lets say that we have a drop down window with some information and we need to display other information in the control's label when the user selects an item. The sample adds two columns, one is displayed in the drop down window, and the second column ( hidden column ) is displayed on the control's label.  

The VB sample looks like follows:

With ComboBox1 .BeginUpdate .AdjustSearchColumn = False .SearchColumnIndex = 1 .HeaderVisible = False .SingleEdit = True .ColumnAutoResize = True .ScrollBySingleLine = True .AllowSizeGrip = True .DrawGridLines = exAllLines .Alignment = LeftAlignment .WidthList = 216 With .Columns.Add("Visible") .Def(exCellSingleLine) = False End With With .Columns.Add("Hidden") .Visible = False End With With .Items Dim h As HITEM h = .AddItem("<b>1.</b> This is a bit of <b>HTML</b> text that should break the line. (HTML text)") .CellCaptionFormat(h, 0) = exHTML .CellCaption(h, 1) = "HTML text" .CellImage(h, 1) = 1 h = .AddItem("<b>2.</b> This is a bit of simple text that should break the line. (Simple text)") .CellCaptionFormat(h, 0) = exHTML .CellCaption(h, 1) = "Simple text" .CellImage(h, 1) = 2 h = .AddItem("<b>3.</b> Standart text") .CellCaptionFormat(h, 0) = exHTML .CellCaption(h, 1) = "Standard text" .CellImage(h, 1) = 3 h = .AddItem("<b>4.</b> Just a long text that should break the line as it should break the line and so break and so on. (Long text)") .CellCaptionFormat(h, 0) = exHTML .CellCaption(h, 1) = "Long text" .CellImage(h, 1) = 2 End With .EndUpdate End With

If we show the "Hidden" column like the sample looks like follows:

For instance you can use this feature if the Style property is DropDownList property to display an owner draw cell in the control's label area. Use the CellOwnerDraw property to draw a cell.

The following sample displays the list of items being checked separated by comma using the control's owner draw feature ( you are simulating a check list editor ):

Implements EXCOMBOBOXLibCtl.IOwnerDrawHandler Option Explicit Private Type RECT left As Long top As Long right As Long bottom As Long End Type Private Declare Function DrawText Lib "user32" Alias "DrawTextA" (ByVal hDC As Long, ByVal lpStr As String, ByVal nCount As Long, lpRect As RECT, ByVal wFormat As Long) As Long Private Const DT_VCENTER = &H4 Private Sub Form_Load() With ComboBox1 .HeaderVisible = False .Style = DropDownList .SingleEdit = True .AllowSizeGrip = True .ColumnAutoResize = True .AdjustSearchColumn = False .LinesAtRoot = exLinesAtRoot .IntegralHeight = True .FullRowSelect = False With .Columns .Add "Column 1" With .Add("owner draw column") .Visible = False ComboBox1.SearchColumnIndex = .Index End With End With With .Items Dim h As HITEM, hC As HITEM, i As Long For i = 1 To 2 h = .AddItem("Item " & i) .CellHasCheckBox(h, 0) = True Set .CellOwnerDraw(h, 1) = Me hC = .InsertItem(h, , "Child 1") .CellHasCheckBox(hC, 0) = True Set .CellOwnerDraw(hC, 1) = Me hC = .InsertItem(h, , "Child 2") .CellHasCheckBox(hC, 0) = True Set .CellOwnerDraw(hC, 1) = Me .ExpandItem(h) = True If (i = 1) Then .SelectItem(h) = True End If Next End With End With End Sub Private Sub IOwnerDrawHandler_DrawCell(ByVal hDC As Long, ByVal left As Long, ByVal top As Long, ByVal right As Long, ByVal bottom As Long, ByVal Item As Long, ByVal Column As Long, ByVal Source As Object) Dim rc As RECT With rc .left = left + 3 .right = right .top = top .bottom = bottom End With Dim s As String s = "" With ComboBox1 Dim i For Each i In .Items If (.Items.CellState(i, 0) = 1) Then s = s + IIf(Len(s) > 0, ",", "") + .Items.CellCaption(i, 0) End If Next End With DrawText hDC, s, Len(s), rc, DT_VCENTER End Sub

The sample adds two columns. The hidden column is used to let user paint whatever he needs.

The following C++ sample adds two columns, and displays values from the hidden column when a new items is selected:

COleVariant vtMissing; V_VT( &vtMissing ) = VT_ERROR; m_combobox.BeginUpdate(); m_combobox.SetAdjustSearchColumn( FALSE ); m_combobox.SetSearchColumnIndex( 1 ); m_combobox.SetHeaderVisible( FALSE ); m_combobox.SetSingleEdit( TRUE ); m_combobox.SetColumnAutoResize( TRUE ); m_combobox.SetScrollBySingleLine( TRUE ); m_combobox.SetAllowSizeGrip( TRUE ); m_combobox.SetDrawGridLines( 1 ); m_combobox.SetAlignment( 0 ); m_combobox.SetWidthList( vtMissing, 216 ); CColumns columns = m_combobox.GetColumns(); CColumn column1( V_DISPATCH( &columns.Add( "Visible" ) ) ); column1.SetDef( 16, COleVariant( VARIANT_FALSE ) ); CColumn column2( V_DISPATCH( &columns.Add( "Hidden" ) ) ); column2.SetVisible( FALSE ); CItems items = m_combobox.GetItems(); COleVariant vtSColumn(long(1)), vtItem = items.AddItem( COleVariant( "1. This item is shown in the drop down portion of the control. The second column displays information in the control's label." ) ); items.SetCellCaption( vtItem, vtSColumn, COleVariant( "Item 1" ) ); vtItem = items.AddItem( COleVariant( "2. This part is never shown in the control's label area." ) ); items.SetCellCaption( vtItem, vtSColumn, COleVariant( "Item 2" ) ); m_combobox.EndUpdate();

The following VB.NET sample adds two columns, and displays values from the hidden column when a new items is selected:

With AxComboBox1 .BeginUpdate() .AdjustSearchColumn = False .SearchColumnIndex = 1 .HeaderVisible = False .SingleEdit = True .ColumnAutoResize = True .ScrollBySingleLine = True .AllowSizeGrip = True .DrawGridLines = EXCOMBOBOXLib.GridLinesEnum.exAllLines .Alignment = EXCOMBOBOXLib.AlignmentEnum.LeftAlignment .set_WidthList(216) With .Columns.Add("Visible") .Def(EXCOMBOBOXLib.DefColumnEnum.exCellSingleLine) = False .Def(EXCOMBOBOXLib.DefColumnEnum.exCellCaptionFormat) = EXCOMBOBOXLib.CaptionFormatEnum.exHTML End With With .Columns.Add("Hidden") .Visible = False End With With .Items Dim h As Integer = .AddItem("<b>1.</b> This is a bit of <b>HTML</b> text that should break the line. (HTML text)") .CellCaption(h, 1) = "HTML text" .CellImage(h, 1) = 1 h = .AddItem("<b>2.</b> This is a bit of simple text that should break the line. (Simple text)") .CellCaption(h, 1) = "Simple text" .CellImage(h, 1) = 2 h = .AddItem("<b>3.</b> Standart text") .CellCaption(h, 1) = "Standard text" .CellImage(h, 1) = 3 h = .AddItem("<b>4.</b> Just a long text that should break the line as it should break the line and so break and so on. (Long text)") .CellCaption(h, 1) = "Long text" .CellImage(h, 1) = 2 End With .EndUpdate() End With

The following C# sample adds two columns, and displays values from the hidden column when a new items is selected:

axComboBox1.BeginUpdate(); axComboBox1.AdjustSearchColumn = false; axComboBox1.SearchColumnIndex = 1; axComboBox1.HeaderVisible = false; axComboBox1.SingleEdit = true; axComboBox1.ColumnAutoResize = true; axComboBox1.ScrollBySingleLine = true; axComboBox1.AllowSizeGrip = true; axComboBox1.DrawGridLines = EXCOMBOBOXLib.GridLinesEnum.exAllLines; axComboBox1.Alignment = EXCOMBOBOXLib.AlignmentEnum.LeftAlignment; axComboBox1.set_WidthList(216); EXCOMBOBOXLib.Columns columns = axComboBox1.Columns; EXCOMBOBOXLib.Column column = columns.Add("Visible") as EXCOMBOBOXLib.Column; column.set_Def(EXCOMBOBOXLib.DefColumnEnum.exCellSingleLine, false); column.set_Def(EXCOMBOBOXLib.DefColumnEnum.exCellCaptionFormat,EXCOMBOBOXLib.CaptionFormatEnum.exHTML); column = columns.Add("Hidden") as EXCOMBOBOXLib.Column; column.Visible = false; EXCOMBOBOXLib.Items items = axComboBox1.Items; int h = items.AddItem("<b>1.</b> This is a bit of <b>HTML</b> text that should break the line. (HTML text)"); items.set_CellCaption(h, 1, "HTML text" ); items.set_CellImage(h, 1, 1); h = items.AddItem("<b>2.</b> This is a bit of simple text that should break the line. (Simple text)"); items.set_CellCaption(h, 1,"Simple text"); items.set_CellImage(h, 1, 2); h = items.AddItem("<b>3.</b> Standart text"); items.set_CellCaption(h, 1,"Standard text"); items.set_CellImage(h, 1, 3); h = items.AddItem("<b>4.</b> Just a long text that should break the line as it should break the line and so break and so on. (Long text)"); items.set_CellCaption(h, 1,"Long text"); items.set_CellImage(h, 1,2); axComboBox1.EndUpdate();

The following VFP sample adds two columns, and displays values from the hidden column when a new items is selected:

With thisform.ComboBox1 .BeginUpdate .AdjustSearchColumn = .f. .SearchColumnIndex = 1 .HeaderVisible = .f. .SingleEdit = .t. .ColumnAutoResize = .f. .ScrollBySingleLine = .t. .AllowSizeGrip = .t. .DrawGridLines = 1 && exAllLines .Alignment = 0 && LeftAlignment .WidthList = 216 With .Columns.Add("Visible") .Def(16) = .f. && exCellSingleLine .Def(17) = 1 && exHTML EndWith With .Columns.Add("Hidden") .Visible = .f. EndWith With .Items .DefaultItem = .AddItem("<b>1.</b> This is a bit of <b>HTML</b> text that should break the line. (HTML text)") .CellCaption(0, 1) = "HTML text" .CellImage(0, 1) = 1 .DefaultItem = .AddItem("<b>2.</b> This is a bit of simple text that should break the line. (Simple text)") .CellCaption(0, 1) = "Simple text" .CellImage(0, 1) = 2 .DefaultItem = .AddItem("<b>3.</b> Standart text") .CellCaption(0, 1) = "Standard text" .CellImage(0, 1) = 3 h = .AddItem("<b>4.</b> Just a long text that should break the line as it should break the line and so break and so on. (Long text)") .CellCaption(0, 1) = "Long text" .CellImage(0, 1) = 2 EndWith .EndUpdate EndWith

 

 

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