Questions on Usage of a .NET Component from VB6 and VBScript

• Thursday, October 16, 2008 12:52 PM

   

   
  

  0
   Hi All,

  We are dealing with .NET server component and COM clients written with VB6 and VBScript. And there are some problems we faced (please see code below).

   1.       Managed type System Drawing.Color is automatically marshaled to VB type OLE_COLOR only in case of early binding. (see DealWithColor() method).

   2.       For class Component public variable DateTime dt can be used in both early and late binding cases, whereas public variable Color clr causes failure in late binding and works fine in early binding.

   3.   Method  public void Info(MyPointClass pt) works fine with VB6 for both early and late binding but fails in VBScript.

            [ComVisible(true)]

      public struct MYPOINT

      {

          // These are now private!

          private int xPos;

          private int yPos;

   

          [MarshalAs(UnmanagedType.BStr)]

          private string name;

   

          // Add some members to the MYPOINT struct.

          public void SetPoint(int x, int y) { xPos = x; yPos = y; }

          public void DisplayPoint() { MessageBox.Show(string.Format("X: {0} Y: {1}", xPos, yPos), name); }

      }

   

      [ComVisible(true)]

      [ClassInterface(ClassInterfaceType.AutoDual)]

      public class MyPointClass

      {

          private int xPos;

          private int yPos;

          private string name;

   

          public void SetPoint(string name, int x, int y) { this.name = name; xPos = x; yPos = y; }

          public void DisplayPoint() { MessageBox.Show(string.Format("X: {0} Y: {1}", xPos, yPos), name); }

      }

   

  [ComVisible(true)]

  [ClassInterface(ClassInterfaceType.AutoDual)]

  public class Component

  {

        // Success in Early Binding. Failure in Late Binding (Both VB6 and VBScript)

        public Color clr;

   

        // Success in Early Binding and Late Binding (Both VB6 and VBScript)

        public DateTime dt;

   

        // Success in Early Binding. Failure in Late Binding (Both VB6 and VBScript)

  public Color DealWithColor(Color col)

        {

            MessageBox.Show(col.ToString(), "DealWithColor() Method");

            return col;

        }

   

  // Success in Early Binding. TODO Late

  public void Info(ref MYPOINT pt)

        {

            pt.DisplayPoint();

        }

   

        // Success in Early Binding and Late Binding (Both VB6 and VBScript)

        public void Info (object pt)

        {

            (pt as MyPointClass).DisplayPoint();

        }

   

  // Success in Early Binding and in Late Binding VB6. Failure in VBScript.

        public void Info (MyPointClass pt)

        {

            pt.DisplayPoint();

        }

  }

   

   

   

      'Late Binding via VB6

      ''''''''''''''''''''''''''''''''''

      Dim ptc As CallNetFromVB6.MyPointClass

      Dim col1 As OLE_COLOR

      Dim objLate As Object

      Set objLate = CreateObject("CallNetFromVB6.Component")

     

      objLate.dt = Now                      'Success

    

      Set ptc = New CallNetFromVB6.MyPointClass

      ptc.SetPoint "From Class", 11, 22

      objLate.Info_2 ptc                           'Success

   

      objLate.clr = vbRed                    'Fail

      col1 = objLate.DealWithColor(col)     'Fail

     

   

      'Late Binding via VBScript

      ''''''''''''''''''''''''''''''''''

      Set objLate = CreateObject("CallNetFromVB6.Component")

      Set ptLate = CreateObject("CallNetFromVB6.MyPointClass")

     

      objLate.dt = Now                      'Success

    

      Set ptc = New CallNetFromVB6.MyPointClass

      ptc.SetPoint "From Class", 11, 22

      objLate.Info_2 ptc                           'Fail

   

      objLate.clr = vbRed                    'Fail

      col1 = objLate.DealWithColor(col)     'Fail

   

   Thanks.

  Igor Ladnik

  Barak Cohen