Microsoft KB Archive/201197

= How To Use a ComboBox to Enter Data into a FlexGrid Control =

Article ID: 201197

Article Last Modified on 7/13/2004

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APPLIES TO


 * Microsoft Visual Basic 5.0 Learning Edition
 * Microsoft Visual Basic 6.0 Learning Edition
 * Microsoft Visual Basic 5.0 Professional Edition
 * Microsoft Visual Basic 6.0 Professional Edition
 * Microsoft Visual Basic 5.0 Enterprise Edition
 * Microsoft Visual Basic 6.0 Enterprise Edition

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This article was previously published under Q201197



SUMMARY
You can use a ComboBox that appears over the active cell to make it easier to enter data into a MSFlexGrid or MSHFlexGrid control. This article demonstrates how to do this, as well as how to resize the ComboBox when a column is resized. Please note that you can only adjust the width of the ComboBox.

The subclassing (or hook) of the FlexGrid control is optional. Its purpose in this article is to resize the ComboBox dynamically when a column in the FlexGrid is resized.



Steps to Create Sample Project
 Start a new Standard EXE project in Visual Basic. Form1 is created by default. On the Project menu, click Components, select Microsoft FlexGrid Control, and click OK. Add a ComboBox and MSFlexGrid control to Form1.  Place the following code into the Form's module:

Option Explicit

Private Sub Form_Unload(Cancel As Integer) If IsHooked Then Unhook  ' Stop checking messages. End If     End Sub

Private Sub MSFlexGrid1_MouseUp(Button As Integer, _        Shift As Integer, x As Single, y As Single) Static CurrentWidth As Single ' Check to see if the Cell's width has changed. If MSFlexGrid1.CellWidth <> CurrentWidth Then Combo1.Width = MSFlexGrid1.CellWidth CurrentWidth = MSFlexGrid1.CellWidth End If     End Sub

Private Sub Form_Load gHW = MSFlexGrid1.hWnd Hook  ' Start checking messages. MSFlexGrid1.AllowUserResizing = flexResizeColumns MSFlexGrid1.Cols = 4 MSFlexGrid1.Rows = 6 MSFlexGrid1.RowHeightMin = Combo1.Height Combo1.Visible = False Combo1.ZOrder (0) Combo1.Width = MSFlexGrid1.CellWidth ' Load the ComboBox's list. Combo1.AddItem "Some text" Combo1.AddItem "Some more text" Combo1.AddItem "Still more text" Combo1.AddItem "Yet even more text" Combo1.AddItem "Way more text than that" End Sub

Private Sub MSFlexGrid1_Click ' Position and size the ComboBox, then show it. Combo1.Width = MSFlexGrid1.CellWidth Combo1.Left = MSFlexGrid1.CellLeft + MSFlexGrid1.Left Combo1.Top = MSFlexGrid1.CellTop + MSFlexGrid1.Top Combo1.Text = MSFlexGrid1.Text Combo1.Visible = True End Sub

Private Sub Combo1_Click ' Place the selected item into the Cell and hide the ComboBox. MSFlexGrid1.Text = Combo1.Text Combo1.Visible = False End Sub   On the Project menu, add a new Module and insert the following code:

Option Explicit

Declare Function CallWindowProc Lib "user32" Alias _ "CallWindowProcA" (ByVal lpPrevWndFunc As Long, _        ByVal hWnd As Long, ByVal Msg As Long, _         ByVal wParam As Long, ByVal lParam As Long) As Long

Declare Function SetWindowLong Lib "user32" Alias _ "SetWindowLongA" (ByVal hWnd As Long, _        ByVal nIndex As Long, ByVal dwNewLong As Long) As Long

Private Const GWL_WNDPROC = -4 Private IsHooked As Boolean Private Const WM_SIZE = &H5 Private Const WM_PAINT = &HF Private lpPrevWndProc As Long Public gHW As Long

Public Sub Hook If IsHooked Then ' Do not hook it twice without unhooking, ' or you will not be able to unhook it. Else lpPrevWndProc = SetWindowLong(gHW, GWL_WNDPROC, _            AddressOf WindowProc) IsHooked = True End If     End Sub

Public Sub Unhook Dim temp As Long temp = SetWindowLong(gHW, GWL_WNDPROC, lpPrevWndProc) IsHooked = False End Sub

Function WindowProc(ByVal hw As Long, ByVal uMsg As _        Long, ByVal wParam As Long, ByVal lParam As Long) As Long WindowProc = CallWindowProc(lpPrevWndProc, hw, _            uMsg, wParam, lParam) ' The interior of the control is repainted, but not resized. If uMsg = WM_SIZE Or uMsg = WM_PAINT Then Form1.Combo1.Width = Form1.MSFlexGrid1.CellWidth Form1.Combo1.Left = Form1.MSFlexGrid1.CellLeft + _ Form1.MSFlexGrid1.Left Form1.Combo1.Top = Form1.MSFlexGrid1.CellTop + _ Form1.MSFlexGrid1.Top End If     End Function  On the File menu, click Save and build an executable. Please do not ignore this step. The use of AddressOf in the IDE can cause the system to crash. Please see the REFERENCES section of this article for more information about this issue. Run the EXE and click in a cell of the FlexGrid. The ComboBox should appear and cover the cell. With the ComboBox showing, use the mouse to widen that column. When you release the mouse button the ComboBox should also adjust in size. This is handled by the code that hooks into the Window's messages. When you select from the ComboBox's list, your choice is added to the cell.</li></ol>

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