Connected (3) Class code: (due to the limit of the number of words per article, I have to develop, forgive me!)
'------------------------------------- ---------------------
'Auxiliary method
'------------------------------------- ---------------------
Private Readonly Property DataGridTableGridLineWidth () AS Integer
Get
If Me.DataGridtablesTyle.GridLineStyle = DataGridLineStyle.solid THEN
Return 1
Else
Return 0
END IF
END GET
End Property
Private sub eyesidit ()
INEDIT = FALSE
Invalidate ()
End Sub
Private function gettext (byval value as object) AS String
IF value is system.dbnull.value the return nulltext
IF not value is nothing then
Return Value.toString
Else
Return String.empty
END IF
END FUNCTION
Private sub hidecomboBox () Hide ComboBox
IF combo.focused the
Me.DataGridtablestyle.DataGrid.foCus ()
END IF
Combo.visible = false
End Sub
Private sub rollback ()
Combo.Text = OldVal
End Sub
Private sub painttext (Byval g as graphics, _
Byval Bounds as Rectangle, _
Byval text as string, _
Byval aligntoright as boolean)
DIM BACKBRUSH AS BRUSH = New Solidbrush (Me.DataGridtablestyle.backcolor)
Dim forebrush as brush = new solidbrush (me.datagridtablestyle.ForeColor)
PaintText (G, Bounds, Text, Backbrush, Forebrush, Aligntoright)
End Sub
Private sub painttext (Byval g as graphics, _
Byval TextBounds as Rectangle, _
Byval text as string, _
Byval backbrush as brush, _
Byval forebrush as brush, _
Byval aligntoright as boolean)
Dim Rect As Rectangle = TextBounds
DIM Rectf as Rectanglef = RectF.op_implicit (rect) to Rectanglef Type
DIM FORMAT AS STRINGFORMAT = New StringFormat ()
IF aligntoright kil
Format.formatflags = stringformatflags.directionrightttoleft
End ifselect case me.alignment
Case is = horizontalalignment.Left
Format.Alignment = stringalignment.near
Case is = horizontalignment.right
Format.Alignment = stringalignment.far
Case is = horizontalalight.center
Format.Alignment = stringalignment.center
End SELECT
Format.formatflags = format.formatflags or stringFormatflags.nowrap
G.FillRectangle (brush: = backbrush, reference: = rect)
Rect.offset (0, ymargin)
Rect.height - = ymargin
g.drawstring (Text, Me.DataGridtablesTyle.DataGrid.font, forebrush, restf, format)
Format.dispose ()
End Sub
END CLASS
4. Use of class
How to use this class? The method is actually very simple, it looks like DataGridTextBoxColumn or DataGridBoolColumn. See here: Database name is northwind.mdb
Private subfrmdropdowncolumn_load (Byval e as system.eventargs) Handles mybase.load
Dim ObjcuStomercm As CurrencyManager
DIM ObjcuStomertablesTyle As DataGridTableStyle
Dim Objgridcol as DataGridColumnstyle
DIM INTAVGCHARWIDTH AS INTEGER
'New a DataSet object
_CUSTOMERDS = New Dataset ()
'New a DataTable object
_STATESDT = New DataTable ()
'New a DataGridTableStyle object
GridtableStyle = new dataGridtableStyle ()
'Calculate the width of each character
With graphics.fromhwnd (me.handle) .measureString (Text: = "AbcdefghijklmnopqrStuvwxyz", font: = me.font)
INTAVGCHARWIDTH = CINT (.width / 26!)
End with
'Establish connections to your database
_Db = new oledbconnection ()
Try
With _db
.Connectionstring = "provider = microsoft.jet.Oledb.4.0;" & _
"Data Source = C: /NorthWind.mdb"
.Open ()
End with
Catch DBERROR AS OLEDBEXCEPTION
STOP
END TRY
_Db.close ()
'
'Newly generated a SQL statement and newly built a user table in DataSet
STRSQL = "SELECT * FROM Customer WHERE National =" & Chr (34) & "US" & Chr (34) & "Order By Customer ID ASC" TRY
With new oledbdataadapter (selectcommand: = new oledbcommand (cmdtext: = strsql, _
Connection: = _ dB))
.Fill (DataSet: = _ CustomerDS, SRCTABLE: = "CUSTOMERS")
.Dispose ()
End with
Catch DBERROR AS OLEDBEXCEPTION
STOP
END TRY
'Connects with data sources related to drop-down box content
_Db = new oledbconnection ()
Try
With _db
.Connectionstring = "provider = microsoft.jet.Oledb.4.0;" & _
"Data Source = C: /NorthWind.mdb"
.Open ()
End with
Catch DBERROR AS OLEDBEXCEPTION
STOP
END TRY
_Db.close ()
'Creating a SQL statement
Strsql = "Select * from States Order by Country ASC"
Try
With new oledbdataadapter (selectcommand: = new oledbcommand (cmdtext: = strsql, _
Connection: = _ dB))
.Fill (DataSet: = _ CustomerDS, SRCTABLE: = "Country")
.Dispose ()
End with
Catch DBERROR AS OLEDBEXCEPTION
STOP
END TRY
With _CUSTOMERDS.TABLES
Objcustomercm = ctype (me.bindingcontext (.Item (name: = "Customers"), currencymanager
End with
'Generate display information
With GridtableStyle
. Mappingname = "Customers"
With .gridcolumnstyles
.Add (Column: = New DataGridTextBoxColumn (ObjcuStomercm. _
GetItemProperties.Item (name: = "Address"))))))))))
With .Item (index: = 0)
. Mappingname = "Address"
.HEADERTEXT = "Address"
.Alignment = horizontalalignment.Left
.Width = intavgcharwidth * 20
.Nulltext = String.empty
End with
_STATESDT = _CUSTOMERDS.TABLES.ITEM ("Country")
.Add (colorcomn: = new DataGridcomboBoxColumn (DataSource: = _ statesdt, _
DisplayMember: = 0, _
ValueMember: = 0)))
With .Item (INDEX: = 1)
. Mappingname = "Country". HEADERTEXT = "Country"
.Alignment = horizontalalignment.Left
.Width = intavgcharwidth * 10
.Nulltext = String.empty
End with
.Add (Column: = New DataGridTextBoxColumn (ObjcuStomercm. _
GetItemProperties.Item (name: = "City"))))))))))))
With .Item (index: = 2)
. Mappingname = "city"
.Headertext = "City"
.Alignment = horizontalalignment.Left
.Width = intavgcharwidth * 20
.Nulltext = String.empty
End with
End with
End with
With entrygrid
.CaptionText = String.empty
.Datasource = _CUSTOMERDS
.DataMember = "Customers"
.Tables.add (Table: = GridTableStyle)
End with
End Sub
Acknowledgment: This program refers to the number of online implementations, and he means to the original author.
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Disclaimer: The right to copyright and interpretation of this article belongs to Han Rui, if you need to reprint, please keep your full content and this statement.
