How do I show Error Message using Managed Custom Actions with Windows Installer

I am writing a managed custom action. I am using the DTF Framework from Windows Installer Xml to wrap the managed dll into a usable CA dll. The CA does what it is supposed to, but I am still having trouble with error handling:

Dim record As New Record(1)

' Field 0 intentionally left blank
' Field 1 contains error number
record(1) = 27533
session.Message(InstallMessage.Error, record)

The above code produces the following text shown in the MSI log:

MSI (c) (C4 ! C6) [13:15:08:749]: Product: TestMSI -- Error 27533. The case-sensitive passwords do not match.

The error number refers to the code contained in the Error table within the MSI. The Message shown above is correct.

My problem is: Why does Windows Installer NOT create a dialog notifying the user about the error?

From stackoverflow

• If you want a dialog to show up that contains the message, you must do it yourself.

  Here's some code I use to do error handling in managed custom actions that run SQL. It shows a messagebox if the installation is operating with a full UI. It's in c# but hopefully you'll get the idea.

   private void _handleSqlException(SqlException ex)
   {
    StringBuilder errorMessage = new StringBuilder();
    errorMessage.Append("A SQL error has occurred.");
    for (int i = 0; i < ex.Errors.Count; i++)
    {
     errorMessage.Append("Index #" + i + "\n" +
      "Message: " + ex.Errors[i].Message + "\n" +
      "LineNumber: " + ex.Errors[i].LineNumber + "\n" +
      "Source: " + ex.Errors[i].Source + "\n" +
      "Procedure: " + ex.Errors[i].Procedure + "\n");
    }
    session.Log(errorMessage);
    if (session["UILevel"] == "5")
    {
     MessageBox.Show(errorMessage);
    }
   }
  

• MSI can do this, but you need to OR in some extra values for the messageType argument.

  eg.

  Record record = new Record();
  record.FormatString = string.Format("Something has gone wrong!");
  
  session.Message(
      InstallMessage.Error | (InstallMessage) ( MessageBoxIcon.Error ) |
      (InstallMessage) MessageBoxButtons.OK,
      record );
  

  See this thread from the wix-users mailing list for more details.

• Hi thanks for the info.

  Do you know if there is a way too show big messages? When i use:

  Record record = new Record(); record.FormatString = pReallyBigMessage;

              Session.Message(InstallMessage.Error | (InstallMessage)System.Windows.Forms.MessageBoxIcon.Warning |
                  (InstallMessage)System.Windows.Forms.MessageBoxButtons.OK, record);
  

  Only parts are displayed. I would like to stick with the Session.Message functionality and not use the Windows.Forms Messagebox because of the focus.

  Greetings

• Here is a walk-through concurring with ayeko's post.

  leogdion : Here is more information on showing a dialog or messagebox in a custom installer. http://social.msdn.microsoft.com/Forums/en-US/winformssetup/thread/bbe69f12-8908-4c65-aa89-1963720d4c11