How To Use RDS to Access MTS Components Over the Internet (247865)


The information in this article applies to:

  • Microsoft Transaction Server 2.0
This article was previously published under Q247865

SUMMARY

This article explains how to use Remote Data Services (RDS) from a Visual Basic client to access your MTS components through HTTP. This service is useful when you want to extend the reach of your MTS applications beyond your local Intranet or a Web browser that uses ASP.

RDS is a programming model that uses an intermediate service, such as IIS, to obtain and manipulate data and objects. This intermediate service actually creates the object and allows the client code to access that object as if the client created the object itself. The complete object model and documentation for RDS can be found here:

http://msdn.microsoft.com/library/en-us/dnoledb/html/usingthecustomizationhandlerfeatureinrds21.asp

MORE INFORMATION

IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows Registry


WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

Following is an explanation illustrating how to create an MTS component, installing the component into MTS, and creating a Visual Basic client application that access the MTS component through HTTP.

Create a Simple MTS Component

  1. Create a new ActiveX DLL project.
  2. Rename the project to "Calculate" and Class1 to CCalculate.
  3. Insert the following code into the CCalculate class module: 
    Public Function GetSum(ByVal Num1 As Integer, ByVal Num2 As Integer) As Integer
  GetSum = Num1 + Num2
End Function
  4. Compile the project and make the DLL.
Setting up MTS

  1. Install the compiled DLL into MTS.
  2. Create a new Package in the MTS Explorer and set it's Identity to run as a user other than Interactive.
  3. Add the Calculate.dll file to the components folder.
  4. In order to get RDS to invoke the MTS component, a registry key must be added that tells IIS that it is ok to create your object.
  5. Add the following key:

    \HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W3SVC\Parameters\ADCLaunch\Calculate.CCalculate
Create the Visual Basic Client

  1. Begin by creating a new Standard EXE project.
  2. On Form1 add two Text Boxes (Text1 and Text2) and a Command Button (Command1).
  3. Add the following code to the Form:

    Private Sub Command1_Click()
  Dim rds As Object
  Dim objCCalculate As Object

  Set rds = CreateObject("RDS.DataSpace")
  Set objCCalculate = rds.CreateObject("Calculate.CCalculate", "http://YourHTTPServerName")

  MsgBox objCCalculate.GetSum(CInt(Text1), CInt(Text2))

  Set rds = Nothing
  Set objCCalculate = Nothing
End Sub
When the client executes and you click Command, RDS asks the Web Server to create the MTS object. The Web Server then returns a reference to the MTS object and the client can use the reference as it would any other MTS object.

REFERENCES

For additional information, click the article number below to view the article in the Microsoft Knowledge Base:

166277 How To Create a VB Component that Returns a Recordset in RDS

Modification Type:MajorLast Reviewed:5/10/2006
Keywords:kbDatabase kbhowto KB247865
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