Click to See Complete Forum and Search --> : HELP!! VB to C# problem for you C# guru's


pcplayer
May 5th, 2008, 03:55 PM
.Net 1.1
I have created a dll in VB. This dll sets may different properties I am only having trouble with the dataset property. The APPNVPS is initialized with the user Id and password and sets the values to be consumed by my apps.

This is the code in Vb which works correctly
APPNVPS is a dll call which returns a dataset


Dim newObject As New APPNVPS(USERID, PASSWORD)
Dim dsValues As New DataSet
Dim stValue As String
dsValues = newObject.AppValues
If dsValues.Tables(0).Rows.Count > 0 Then
MessageBox.Show("There are " & dsValues.Tables(0).Rows.Count & " records")
End If
The Message box show that I have 16 record

C# code
DataSet ds = new DataSet();
APPNVPS objApp = new APPNVPS(UserID,Password);
ds = objApp.AppValues;
MessageBox::Show ds.Tables[0].row.count;

Gives me a runtime error <undefined value> null value
I know that I am not fluent in C# but this can't be that difficult.

David Anton
May 5th, 2008, 07:43 PM
That last line would certainly not compile. You seem to be mixing some C++/CLI in there also (the double colon qualifier).

The literal conversion is (via Instant C#):

APPNVPS newObject = new APPNVPS(USERID, PASSWORD);
DataSet dsValues = new DataSet();
string stValue = null;
dsValues = newObject.AppValues;
if (dsValues.Tables[0].Rows.Count > 0)
{
MessageBox.Show("There are " + dsValues.Tables[0].Rows.Count + " records");
}

pcplayer
May 6th, 2008, 03:29 PM
DataSet ds = new DataSet();

APPNVPS objApp = new APPNVPS(UserID,Password);

'Returns property value
string DS = objApp.DataSource;
txtDataSource.Text = DS;

'Returns property value
txtVersion.Text = objApp.Version;

'Assigned to dataset property value
ds = objApp.Printers;

int intCount ;
***intCount = ds.Tables[0].Rows.Count;
txtPrintCount.Text = intCount.ToString();

**I am getting An unhandled Exception 'System.NullReferenceException' **
ds value is <undefined>

Once again this Visual Basic code above works correctly calls the same dll
Thanks

cjard
May 6th, 2008, 05:48 PM
would you please learn to use the formatting buttons? press EDIT, select the portion of your post that is code, and then press the http://www.codeguru.com/forum/images/editor/code.gif button?

similarly for bold, there's a bold button

cjard
May 6th, 2008, 05:53 PM
ps; if you didnt already know, C# is case sensitive. If you want to code in C# effectively youre going to have to smarten up all your sloppy VBad Habits ;)

pcplayer
May 7th, 2008, 10:23 AM
Nice, very insightfull. Thanks