I am trying to draw line.....Actually these codes were previously in vb 6...i tried to change them in vb.net....but every time i try to run the application i got this error ."Object reference not set to an instance of an object"...plz help me regerding this error....here are my code - Sub BeamDraw(ByRef DrawControl As PaintEventArgs, ByRef ds As DAO.Recordset)
-
Dim Y5 As Double
-
Dim X5 As Double
-
Dim Y2 As Double
-
Dim X2 As Double
-
Dim Y3 As Double
-
Dim X3 As Double
-
Dim Y1 As Double
-
Dim X1 As Double
-
Dim szcolumn As String
-
Dim X As Single
-
Dim Y As Single
-
Dim Dc As DAO.Recordset
-
Dim DCC As DAO.Recordset
-
DCC = CurDb.OpenRecordset("Columns", DAO.RecordsetTypeEnum.dbOpenDynaset)
-
Dc = CurDb.OpenRecordset("Columns", DAO.RecordsetTypeEnum.dbOpenDynaset)
-
While Not ds.EOF
-
szcolumn = "Cname='" + ds.Fields(0).Value + "'"
-
DCC.FindFirst(szcolumn)
-
X = DCC.Fields(4).Value
-
Y = DCC.Fields(5).Value
-
X1 = DCC.Fields(4).Value
-
Y1 = DCC.Fields(5).Value
-
FlushDistances(DCC, X, Y)
-
X3 = X
-
Y3 = Y
-
If StrComp(Left(DCC.Fields(0).Value, 1), "C") = 0 Then
-
Select Case DCC.Fields(1).Value
-
Case "H"
-
DrawControl.Graphics.DrawLine(Pens.OrangeRed, CInt(X - DCC.Fields(2).Value / 2), CInt(Y - DCC.Fields(3).Value / 2) - CInt(X + DCC.Fields(2).Value / 2), CInt(Y + DCC.Fields(3).Value / 2), B)
-
-
-
End Select
-
Else
-
Select Case DCC.Fields(1).Value
-
Case "H"
-
DrawControl.Graphics.DrawLine(Pens.OrangeRed, CInt(X - DCC.Fields(2).Value / 2), CInt(Y - DCC.Fields(3).Value / 2) - CInt(X + DCC.Fields(2).Value / 2), CInt(Y + DCC.Fields(3).Value / 2), B)
-
-
End Select
-
End If
-
If Enlarge Or BeamSelect Then
-
Column_Dis(DCC.Fields(4).Value + DCC.Fields(2).Value / 2, DCC.Fields(5).Value - DCC.Fields(3).Value / 2, DCC.Fields(0).Value, DrawControl)
-
End If
-
szcolumn = "Cname='" + ds.Fields(1).Value + "'"
-
Dc.FindFirst(szcolumn)
-
X = (Dc.Fields(4).Value)
-
Y = (Dc.Fields(5).Value)
-
X2 = Dc.Fields(4).Value
-
Y2 = Dc.Fields(5).Value
-
FlushDistances(Dc, X, Y)
-
X5 = X
-
Y5 = Y
-
If X1 = X2 Then
-
CenterFlag = "BeamVertical"
-
Else
-
If Y1 = Y2 Then
-
CenterFlag = "BeamHorizontal"
-
End If
-
End If
-
If StrComp(Left(Dc.Fields(0).Value, 1), "C") = 0 Then
-
Select Case Dc.Fields(1).Value
-
Case "H"
-
DrawControl.Graphics.DrawLine(Pens.OrangeRed, CInt(X - Dc.Fields(2).Value / 2), CInt(Y - Dc.Fields(3).Value / 2), CInt(X + Dc.Fields(2).Value / 2), CInt(Y + Dc.Fields(3).Value / 2))
-
-
End Select
-
Else
-
Select Case Dc.Fields(1).Value
-
Case "H"
-
-
DrawControl.Graphics.DrawLine(Pens.OrangeRed, CInt(X - Dc.Fields(2).Value / 2), CInt(Y - Dc.Fields(3).Value / 2) - CInt(X + Dc.Fields(2).Value / 2), CInt(Y + Dc.Fields(3).Value / 2), B)
-
-
End Select
-
End If
-
-
If Enlarge Or BeamSelect Then
-
Column_Dis(Dc.Fields(4).Value + Dc.Fields(2).Value / 2, Dc.Fields(5).Value - Dc.Fields(3).Value / 2, Dc.Fields(0).Value, DrawControl)
-
End If
-
ShowBeam(ds, DCC, DCC, DrawControl, X3, Y3, X5, Y5, CenterFlag)
-
ds.MoveNext()
-
End While
-
End Sub
5  1212 
It would help if you could provide more information. Do you have a line number where it is occurring or can you trap it?
Well thanks for replying........Actually in my project i have 2 forms one consist of a datagrid and other form consisting of a picture box,,,,,and now when you enter data in first form you can see the drawing of your data in the other form.
also i am using vb.net for first time so if u can help me what should i use for drawing lines ...... system.drawing.graphics or system.windows.forms.paintEventargs
I am trying to draw line.....Actually these codes were previously in vb 6...i tried to change them in vb.net....but every time i try to run the application i got this error ."Object reference not set to an instance of an object"...plz help me regerding this error....here are my code
- Sub BeamDraw(ByRef DrawControl As PaintEventArgs, ByRef ds As DAO.Recordset)
-
Dim Y5 As Double
-
Dim X5 As Double
-
Dim Y2 As Double
-
Dim X2 As Double
-
Dim Y3 As Double
-
Dim X3 As Double
-
Dim Y1 As Double
-
Dim X1 As Double
-
Dim szcolumn As String
-
Dim X As Single
-
Dim Y As Single
-
Dim Dc As DAO.Recordset
-
Dim DCC As DAO.Recordset
-
DCC = CurDb.OpenRecordset("Columns", DAO.RecordsetTypeEnum.dbOpenDynaset)
-
Dc = CurDb.OpenRecordset("Columns", DAO.RecordsetTypeEnum.dbOpenDynaset)
-
While Not ds.EOF
-
szcolumn = "Cname='" + ds.Fields(0).Value + "'"
-
DCC.FindFirst(szcolumn)
-
X = DCC.Fields(4).Value
-
Y = DCC.Fields(5).Value
-
X1 = DCC.Fields(4).Value
-
Y1 = DCC.Fields(5).Value
-
FlushDistances(DCC, X, Y)
-
X3 = X
-
Y3 = Y
-
If StrComp(Left(DCC.Fields(0).Value, 1), "C") = 0 Then
-
Select Case DCC.Fields(1).Value
-
Case "H"
-
DrawControl.Graphics.DrawLine(Pens.OrangeRed, CInt(X - DCC.Fields(2).Value / 2), CInt(Y - DCC.Fields(3).Value / 2) - CInt(X + DCC.Fields(2).Value / 2), CInt(Y + DCC.Fields(3).Value / 2), B)
-
-
-
End Select
-
Else
-
Select Case DCC.Fields(1).Value
-
Case "H"
-
DrawControl.Graphics.DrawLine(Pens.OrangeRed, CInt(X - DCC.Fields(2).Value / 2), CInt(Y - DCC.Fields(3).Value / 2) - CInt(X + DCC.Fields(2).Value / 2), CInt(Y + DCC.Fields(3).Value / 2), B)
-
-
End Select
-
End If
-
If Enlarge Or BeamSelect Then
-
Column_Dis(DCC.Fields(4).Value + DCC.Fields(2).Value / 2, DCC.Fields(5).Value - DCC.Fields(3).Value / 2, DCC.Fields(0).Value, DrawControl)
-
End If
-
szcolumn = "Cname='" + ds.Fields(1).Value + "'"
-
Dc.FindFirst(szcolumn)
-
X = (Dc.Fields(4).Value)
-
Y = (Dc.Fields(5).Value)
-
X2 = Dc.Fields(4).Value
-
Y2 = Dc.Fields(5).Value
-
FlushDistances(Dc, X, Y)
-
X5 = X
-
Y5 = Y
-
If X1 = X2 Then
-
CenterFlag = "BeamVertical"
-
Else
-
If Y1 = Y2 Then
-
CenterFlag = "BeamHorizontal"
-
End If
-
End If
-
If StrComp(Left(Dc.Fields(0).Value, 1), "C") = 0 Then
-
Select Case Dc.Fields(1).Value
-
Case "H"
-
DrawControl.Graphics.DrawLine(Pens.OrangeRed, CInt(X - Dc.Fields(2).Value / 2), CInt(Y - Dc.Fields(3).Value / 2), CInt(X + Dc.Fields(2).Value / 2), CInt(Y + Dc.Fields(3).Value / 2))
-
-
End Select
-
Else
-
Select Case Dc.Fields(1).Value
-
Case "H"
-
-
DrawControl.Graphics.DrawLine(Pens.OrangeRed, CInt(X - Dc.Fields(2).Value / 2), CInt(Y - Dc.Fields(3).Value / 2) - CInt(X + Dc.Fields(2).Value / 2), CInt(Y + Dc.Fields(3).Value / 2), B)
-
-
End Select
-
End If
-
-
If Enlarge Or BeamSelect Then
-
Column_Dis(Dc.Fields(4).Value + Dc.Fields(2).Value / 2, Dc.Fields(5).Value - Dc.Fields(3).Value / 2, Dc.Fields(0).Value, DrawControl)
-
End If
-
ShowBeam(ds, DCC, DCC, DrawControl, X3, Y3, X5, Y5, CenterFlag)
-
ds.MoveNext()
-
End While
-
End Sub
Total stab in the dark by someone who doesn't do VB...
In line 78 you make use of CenterFlag variable.
I see no place where you create this variable (Looks like that is done with the DIM statement as in line 10 ??)
Assuming this is a global variable created elsewhere... Is it ever initialized to a default value? CenterFlag only gets set in Verticle in line 54 if X1=X2 or to Horizontal in line 57 if Y1=Y2. What happens if neither of these conditions exist? Does CenterFlag remain unset later when it is used in line 78?
Well thanks for replying........Actually in my project i have 2 forms one consist of a datagrid and other form consisting of a picture box,,,,,and now when you enter data in first form you can see the drawing of your data in the other form.
also i am using vb.net for first time so if u can help me what should i use for drawing lines ...... system.drawing.graphics or system.windows.forms.paintEventargs
Why don't you just tell us the number reported for that exception?
Total stab in the dark by someone who doesn't do VB...
In line 78 you make use of CenterFlag variable.
I see no place where you create this variable (Looks like that is done with the DIM statement as in line 10 ??)
Assuming this is a global variable created elsewhere... Is it ever initialized to a default value? CenterFlag only gets set in Verticle in line 54 if X1=X2 or to Horizontal in line 57 if Y1=Y2. What happens if neither of these conditions exist? Does CenterFlag remain unset later when it is used in line 78?
Then it Will give us a diagonal Connection....Well Thank u .....
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