Visual Basic

How to capture screen in VB.net?

1-Feb-05 17:28

fo0lish wrote:
frmB.txtpbchat.Text = text & Environment.NewLine & frmB.txtpbchat.Text

First, don't use string concatentation. Use the .AppendText() method of the RichTextBox. Second, position the insertion point to the end of the text before you call .AppendText(). If the insertion point is anywhere else in the text, the color won't be applied correctly.

This is an example:

RichTextBox1.SelectionStart = RichTextBox1.TextLength
RichTextBox1.SelectionColor = System.Drawing.Color.Blue
RichTextBox1.AppendText(text & Environment.NewLine & frmB.txtpbchat.Text)

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

rushing31-Jan-05 21:01

Re: How to capture screen in VB.net?

31-Jan-05 21:01

I use API funcion -- StretchBlt -- to capture screen in VB 6.0 and succeed.
When I copy the code into VB.net, capture failed, nothing happened.
Here is some of the code:

Picture1.Scale(1.5F)
w = Picture1.Width
h = Picture1.Height
hdcScreen = GetDC(0)

r = StretchBlt(Picture1.Handle, 0, 0, w, h, hdcScreen, xSrc, ySrc, wSrc, hSrc, SRCCOPY)

Please give me some samples?
Thanks!

Dave Kreskowiak1-Feb-05 3:52

Re: How to capture screen in VB.net?

1-Feb-05 3:52

First, why are you using StretchBlt instead of BitBlt? Are you recaling the image for magnification purposes?

What does your code look like in VB.NET? We need to see the Declaration you used to import the StretchBlt function. Also, what are the variables you used in this code snippet defined as? 99.999% of problems calling API functions are caused by having an incorrect Declare statement and passing parameters incorrectly.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

rushing1-Feb-05 14:46

1-Feb-05 14:46

I do not know how to use BitBlt, only know StretchBlt function.
Here is the declaration:

Private Declare Ansi Function StretchBlt Lib "gdi32" (ByVal hDC As Long, ByVal x As Long, ByVal y As Long, ByVal nWidth As Long, ByVal nHeight As Long, ByVal hSrcDC As Long, ByVal xSrc As Long, ByVal ySrc As Long, ByVal nSrcWidth As Long, ByVal nSrcHeight As Long, ByVal dwRop As Long) As Long

The whole source code .

rushing1-Feb-05 14:51

Re: The whole source code .

1-Feb-05 14:51

I am afraid the code is too long.

Sub CaptureScreen(ByVal Picture1 As PictureBox, ByVal xSrc As Integer, ByVal ySrc As Integer, ByVal wSrc As Integer, ByVal hSrc As Integer)
Dim w As Long
Dim h As Long
Dim hdcScreen As Long
Dim r As Long
Dim hMemDC As Long

'Dim bmp As Bitmap

Try
'bmp = New Bitmap(wSrc, hSrc)

'Picture1.Scale(1.5F)
w = Picture1.Width
h = Picture1.Height
hdcScreen = GetDC(0)
'hMemDC = CreateCompatibleDC(bmp.GetHbitmap)
hMemDC = GetDC(Picture1.Handle)

r = StretchBlt(hMemDC, 0, 0, w, h, hdcScreen, xSrc, ySrc, wSrc, hSrc, SRCCOPY)

Trace.WriteLine("Picture1.Handle=" + Picture1.Handle.ToString + " hMemDC=" + hMemDC.ToString + ",w=" + w.ToString + ",h=" + h.ToString)
Trace.WriteLine("hdcScreen=" + hdcScreen.ToString)
Trace.WriteLine("xSrc=" + xSrc.ToString + ",ySrc=" + ySrc.ToString + ",wSrc=" + wSrc.ToString + ",hSrc=" + hSrc.ToString)
Trace.WriteLine("r=" + r.ToString + vbCrLf)

Catch ex As Exception
MsgBox(ex.ToString, vbQuestion, "CaptureScreen")
End Try

End Sub

Dave Kreskowiak1-Feb-05 17:59

Synchronize two databases

1-Feb-05 17:59

First, I didn't appreciate the "1" vote. All I asked you was why you were using StretchBlt and to see the RELEVANT parts of your code and I told you which parts those were.

Second, BitBlt is no different than StrechBlt. Actually, it's a bit simpler to use since there aren't as many parameters.

Third, the SDK documenation on both StretchBlt and BitBlt describe their parameters as HDC, which is just a 32-bit value that should be passed as an IntPtr, and int's, which in VB.NET are Integer types, not Long types.

The corrected Declare statement should look like this:

Private Declare Auto Function StretchBlt Lib "gdi32" ( _
        hDC As IntPtr, x As Integer, y As Integer, _
        nWidth As Integer, nHeight As Integer, _
        hSrcDC As IntPtr, xSrc As Integer, ySrc As Integer, _
        nSrcWidth As Integer, nSrcHeight As Integer, dwRop As Integer) _
        As Integer

BTW: Parameters are passed ByVal by default. You don't need to specify it on every parameter.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

Aman Ullah Principal Software Engineer31-Jan-05 21:00

Aman Ullah Principal Software Engineer

31-Jan-05 21:00

i want to synchronize two databases having the same schema at different locations. any body help me.
thanks

Re: Synchronize two databases

Dave Kreskowiak1-Feb-05 3:43

Aman Ullah Principal Software Engineer

1-Feb-05 3:43

Access, mySQL, SQL Server, Oracle, ... ? Which database type?

Oracle and SQL Server has their own replication services that can do this for you. The others, you'll have to write the replicator yourself.

If your going to write it yourself, are your records timestamped? If not, you'll find it VERY difficult to know which records are more recent that the ones in the other database. You'll actually have to create another table in the database to hold the replication tracking information for each record.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

Synchronize two database

Aman Ullah Principal Software Engineer31-Jan-05 20:58

31-Jan-05 20:58

i want to synchronize two databases having the same schema at different locations. any body help me.
Aman

Printing in VB.net (Please Please help me)

Aman Ullah Principal Software Engineer31-Jan-05 18:31

Aman Ullah Principal Software Engineer

31-Jan-05 18:31

hi All
I want to send print to the printer port in vb.net character by character (one character at a time ), not the whole file.
the purpose is like :
for i = 1 to 15

next
value of i shloud be transferred to the printer port at each execution of the FOR LOOP:
the value of i of the for loop that is executed 15 times should be printed.
print should be in this format:
1 2 3 4 5
6 7 8 9 10
11 12 13 14 15 (means value of i)

any body help me please. i need it urgently.
thanks in advance.
Bye

Re: Printing in VB.net (Please Please help me)

Dave Kreskowiak1-Feb-05 3:39

VB.Net and Access Stored Procedures

1-Feb-05 3:39

This topic comes up so often, you should search the forums first.

What your looking for is on MSDN: HOW TO: Send Raw Data to a Printer by Using Visual Basic .NET[^]. It's not as easy as you'd think.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

BlueMurderJay31-Jan-05 16:44

31-Jan-05 16:44

I have been killing myself with this and getting nowhere.

I have an Access DB with a table for clients, among others. I am trying to use a stored procedure (query) to insert a new client. Here is my code for this part:

Public Sub addCustomer()

'Grab the contents of each field
Dim CustNumVal As String = Me.tbxCustNum.Text
Dim CustNameVal As String = Me.cbxCustName.Text
Dim CustContactVal As String = Me.tbxCustContact.Text
Dim CustAdd1Val As String = Me.tbxCustAdd1.Text
Dim CustAdd2Val As String = Me.tbxCustAdd2.Text
Dim CustCityVal As String = Me.tbxCustCity.Text
Dim CustStateVal As String = Me.tbxCustState.Text
Dim CustZipVal As String = Me.tbxCustZip.Text
Dim CustPhoneVal As String = Me.tbxCustPhone.Text
Dim CustFaxVal As String = Me.tbxcustFax.Text
Dim CustEmailVal As String = Me.tbxCustEmail.Text

'Create Command Params
objCommand = New OleDb.OleDbCommand
objCommand.Connection = objConnection
objCommand.CommandType = CommandType.StoredProcedure
objCommand.Parameters.Add("@CustNum", OleDb.OleDbType.Integer, 50, CustNumVal)
objCommand.Parameters.Add("@CustName", OleDb.OleDbType.Char, 50, CustNameVal)
objCommand.Parameters.Add("@CustContact", OleDb.OleDbType.Char, 50, CustContactVal)
objCommand.Parameters.Add("@CustAdd1", OleDb.OleDbType.Char, 50, CustAdd1Val)
objCommand.Parameters.Add("@CustAdd2", OleDb.OleDbType.Char, 50, CustAdd2Val)
objCommand.Parameters.Add("@CustCity", OleDb.OleDbType.Char, 2, CustCityVal)
objCommand.Parameters.Add("@CustState", OleDb.OleDbType.Char, 60, CustStateVal)
objCommand.Parameters.Add("@CustZip", OleDb.OleDbType.Integer, 50, CustZipVal)
objCommand.Parameters.Add("@CustPhone", OleDb.OleDbType.Char, 50, CustPhoneVal)
objCommand.Parameters.Add("@CustFax", OleDb.OleDbType.Char, 50, CustFaxVal)
objCommand.Parameters.Add("@CustEmail", OleDb.OleDbType.VarChar, 50, CustEmailVal)

objCommand.CommandText = "EXECUTE usp_AddCustomer"
objConnection.Open()
objCommand.ExecuteNonQuery()
objConnection.Close()

'Change the style of the drop down list
Me.cbxCustName.DropDownStyle = ComboBoxStyle.DropDownList

'Revert the controls back to read only
Me.tbxCustAdd1.ReadOnly = True
Me.tbxCustAdd2.ReadOnly = True
Me.tbxCustCity.ReadOnly = True
Me.tbxCustContact.ReadOnly = True
Me.tbxCustEmail.ReadOnly = True
Me.tbxCustNum.ReadOnly = True
Me.tbxCustPhone.ReadOnly = True
Me.tbxcustFax.ReadOnly = True
Me.tbxCustState.ReadOnly = True
Me.tbxCustZip.ReadOnly = True

'Hide the buttons
Me.btnAction.Visible = False
Me.btnCancelNew.Visible = False

'Clear and fill the Data Set
DsCustInfo.Clear()
daCustInfo.Fill(DsCustInfo)

'Set the record number to the new record
Dim newRecID As Integer
newRecID = Me.BindingContext(DsCustInfo, "custinfo").Count
Me.BindingContext(DsCustInfo, "custinfo").Position = newRecID

'Cleanup
CustNumVal = Nothing
CustNameVal = Nothing
CustContactVal = Nothing
CustAdd1Val = Nothing
CustAdd2Val = Nothing
CustCityVal = Nothing
CustStateVal = Nothing
CustZipVal = Nothing
CustPhoneVal = Nothing
CustFaxVal = Nothing
CustEmailVal = Nothing
objConnection.Close()

End Sub

The variables, strConnectionString, objConnection and objCommand are delcared at the top of the form as global variables as such:

Inherits System.Windows.Forms.Form
Public strConnectionString As String = "Provider=Microsoft.Jet.OLEDB.4.0;" & _
"Data Source=C:\Documents and Settings\user\My Documents\Visual Studio Projects\" & _
"OnBase Configurator\db1.mdb;"
Public objConnection As New OleDb.OleDbConnection(strConnectionString)
Public objCommand As New OleDb.OleDbCommand

No matter what I do, I keep getting the following error:

An unhandled exception of type 'System.Data.OleDb.OleDbException' occurred in system.data.dll

Someone please help me or shoot me. Either one is fine right now.

Jay Davis

Just Greeky Creek1-Feb-05 1:41

Just Greeky Creek

1-Feb-05 1:41

just use
objCommand.CommandText = "usp_AddCustomer"

BlueMurderJay1-Feb-05 14:39

1-Feb-05 14:39

I tried that to no avail.

I also put the execute in a try...catch block and got a more precise error.

An unhandled exception of type 'System.ArgumentException' occurred in microsoft.visualbasic.dll

Additional information: Argument 'Prompt' cannot be converted to type 'String'.

Is this a dbtype mismatch?

Jay Davis

BlueMurderJay1-Feb-05 14:44

1-Feb-05 14:44

More Info....

Here is the query in Access

It is named usp_AddCustomer

INSERT INTO CustInfo ( CustNum, CustName, CustContact, CustAdd1, CustAdd2, CustCity, CustState, CustZip, CustPhone, CustFax, CustEmail )
SELECT [@CustNum] AS Expr1, [@CustName] AS Expr2, [@CustContact] AS Expr3, [@CustAdd1] AS Expr4, [@CustAdd2] AS Expr5, [@CustCity] AS Expr6, [@CustState] AS Expr7, [@CustZip] AS Expr8, [@CustPhone] AS Expr9, [@CustFax] AS Expr10, [@CustEmail] AS Expr11;

Jay Davis

BlueMurderJay1-Feb-05 16:11

1-Feb-05 16:11

More Info....

I have modified the structure as follows

Try
objCommand = New OleDb.OleDbCommand
objCommand.Connection = objConnection
objCommand.CommandType = CommandType.StoredProcedure
objCommand.Parameters.Add("@CustNum", OleDb.OleDbType.Variant, 50, "99999")
objCommand.Parameters.Add("@CustName", OleDb.OleDbType.Char, 50, "Test1")
objCommand.Parameters.Add("@CustContact", OleDb.OleDbType.Char, 50, "Test User")
objCommand.Parameters.Add("@CustAdd1", OleDb.OleDbType.Char, 50, "123 Your Street")
objCommand.Parameters.Add("@CustAdd2", OleDb.OleDbType.Char, 50, "Apt C")
objCommand.Parameters.Add("@CustCity", OleDb.OleDbType.Char, 50, "Your City")
objCommand.Parameters.Add("@CustState", OleDb.OleDbType.Char, 2, "OH")
objCommand.Parameters.Add("@CustZip", OleDb.OleDbType.Char, 50, "99999")
objCommand.Parameters.Add("@CustPhone", OleDb.OleDbType.Char, 50, "1234567890")
objCommand.Parameters.Add("@CustFax", OleDb.OleDbType.Char, 50, "1234567891")
objCommand.Parameters.Add("@CustEmail", OleDb.OleDbType.VarChar, 50, "test@test.com")

objCommand.CommandText = "usp_AddCustomer"
objConnection.Open()
objCommand.ExecuteNonQuery()
Catch OleDbExceptionErr As OleDbException
MsgBox(OleDbExceptionErr.ToString)
End Try

I am now just trying to do hard coded strings, and when I run it with the try...catch block, I get teh following error:

System.Data.OleDb.OleDbException: Parameter [@CustNum] has no default value.

Jay Davis

Dave Kreskowiak1-Feb-05 18:06

How to use DirectShow in VB.net?

1-Feb-05 18:06

Just to add my 2 cents...

First, forget everything you know about real SQL. Access/Jet doesn't support a lot of it.

Access/Jet doesn't support named parameters. You CAN name them for a bit of clarity when you read the SQL statement, but the names are not used. There parameters you add must be supplied in the same order that they appear in the SQL statement. This also means you can't skip parameters. If a parameter in your statement can be blank, you have to supply it as a blank, null, or 0 value.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

rushing31-Jan-05 14:32