Implement PickList function in VB
Foreword
People who use Delphi programming that the database control DBGRID has a PickList function in Delphi, that is, when editing the column, as long as the column is clicked, the column will appear in the combo box, list all content for users, this is very Convenient data entry. As shown in the figure.
Figure 1. Delphi's PickList function display diagram
Regrettably, the controls provided by VB DBGrid32.ocx is looking for, without the above PickList function.
The above PickList function is still implemented in VB.
Idea:
1. Add a combo box on the form, and the number is exactly the same as the number of columns that need to implement the PickList function.
2, in related events, such as mouse or cursor (ie, focus) position in the Picklist column, display the combo box, its location, the size of the unit is completely coincident, by default, the value of the combination frame is the unit of DBGRID. Value; otherwise the combo box is hidden.
3. Select or enter the relevant information by the user in the ComboBox combo box, and put the information of the combo box into the DBGRID unit.
Implementation process:
For the sake of simplicity, assume that only one column of PickList is only one column, the corresponding database file has been added to the relevant control.
1. Add a new project to add Microsoft Data Bound Control (ie, file dbgrid32.ocx); put the control into the form; envision the record file including name, retirement type, etc., retirement type is second column (for The first column of DBGRID1 is implemented in the PickList function; take DBGrid1.RowHeight = 300, which is equal to the width of the combo box, and does not allow the DBGRID1 line size.
2, add the ComboBox combo combination box, name: CBL retire species; Visible: false ;; Add information in list attribute: such as retirement | Food workers in the country | Retirement | Return | Note: | Representing a newline.).
And put the CBL retirement type on DBGRID1 and placed before;
The main source code for implementing the PickList function is as follows:
Option expedition
DIM LASTRECNUM AS INTEGER 'Record the location of the composite box content change
Private Sub CBL Retirement Type Show_Lostfocus ()
'Update record value
DIM CURRECNUM 'Current record number
With data1.recordset
CurRecnum = .AbsolutePosition 1
.MOVEFIRST
.MOVE LASTRECNUM - 1
. Ait
.Fields (1) = frmPick.cbl retire species display
.Update
'Refractive location
.MOVE CURRECNUM - LastRecnum
End with
End Sub
'Pay attention to the following three events
Private sub DBGRID1_ROWCOLCHANGE (Lastrow As Variant, Byval Lastcol as inTeger)
DisplayComboBox
End Sub
Private sub DBGRID1_COLRESIZE (Byval Colindex As Integer, Cancel AS Integer)
DisplayComboBox
End Sub
Private sub DBGRID1_Scroll (Cancel AS Integer)
Cancel = false
'Combination frame disappears
Doevents
FRMPICK.CBL Retirement Type Show .visible = falseEnd Sub
Sub DisplayComboBox ()
The operation that should be made to the combination box when it meets the conditions. The key to the process is the key to the article.
'The location where the current record is
LastRecnum = data1.recordset.absoluteposition 1
'frmPick.caption = data1.recordset.fields (1) .value
WITH FRMPICK.CBL Retirement species display
'When the cursor or mouse is listed in the Retirement Type,
IF dbgrid1.col = 1 THEN
The 'combo box appears and has a focus;
.Visible = TRUE
.Setfocus
IF dbgrid1.columns (1) = "" "
.Text = .list (0)
Else
.Text = dbgrid1.columns (1)
END IF
'CBL retirement species display location
'left:
Dim RecordtitleWidth 'Record Head Width
RecordTITLEWIDTH = 280 'This value does not know how to get it, this department is gradually adjusted;
.Left = recorditlewidth DBGRID1.LEFT GETLEFTCOLPOS
Dim colheadheight 'column
COLHEADHEIGHT = 220 'This value still does not know how to acquire, this department is gradually adjusted;
.Top = dbgrid1.top dbgrid1.row * DBGRID1.ROWHEIGHT COLHEADHEIGHT
.Width = dbgrid1.columns (1) .width
END IF
'When the cursor is not in the PickList column
IF dbgrid1.col <> 1 THEN
.Visible = false
END IF
End with
End Sub
Function GetLeftColpos ()
The left side of the 'DBGRID1 control can be seen that the packet implementation picklist column
DIM I
i = dbgrid1.Leftcol
GetleftColpos = 0
IF i <1 THEN
Do WHILE I <1 'The column 1 of the site 1 Realize the column of PickList
GetleftColpos = GetleftColpos DBGRID1.COLUMNS (i) .width
i = i 1
Loop
END IF
IF i> 1 THEN
Do While i> 1 'The column of the site 1 Realize the column of PickList
GetleftColpos = GetleftColpos - DBGRID1.COLUMNS (i) .width
i = i - 1
Loop
END IF
END FUNCTION
Figure 2 is an example of a PickList function written in VB code.
Figure 2, implement the column of dbgrid with VB code PickList example
The above code is passed in VB6.0, Windows98 Chinese version.
