Filling in a docvariable in Word docx using C#

Question

I've done this a hundred times in VB 6 but it's driving me nuts using C# 2008 and Word 2007. I created a docx file with two docvariables:

Some text here....

{docvariable replace1}
{docvariable replace2}

More text here......

I created a macro first to do it and it works:

Sub FillDocVariable()
'
' FillDocVariable Macro
'
'

  ActiveDocument.Variables("replace1").Value = "This is a test"
  ActiveDocument.Variables("replace2").Value = "it is only a test."
  ActiveDocument.Fields.Update

End Sub

Here's my C# code (mind you I'm learning this as I go):

using Microsoft.Office.Interop.Word;
 object paramMissing = Type.Missing;
       object openfileName = @"C:\testing\Documents\1.docx";

      ApplicationClass WordApplication = new ApplicationClass();
      Document WordDocument = WordApplication.Documents.Open(ref openfileName, 
        ref paramMissing, ref paramMissing, ref paramMissing,
        ref paramMissing, ref paramMissing, ref paramMissing,
        ref paramMissing, ref paramMissing, ref paramMissing,
        ref paramMissing, ref paramMissing, ref paramMissing,
        ref paramMissing, ref paramMissing, ref paramMissing);

      WordDocument.Variables("replace1") = "This is a test";
      WordDocument.Variables("replace2").Value = "it's only a test!";
      WordDocument.Fields.Update;

Here's the error I get:

Error 1 Non-invocable member 'Microsoft.Office.Interop.Word._Document.Variables' cannot be used like a method. Blockquote

Any help will be greatly appreciated.

Answer 1

The first guess: WordDocument.Variables("replace1") → WordDocument.Variables["replace1"].

Update after finding it in MSDN: Apparently, the indexer is a ref parameter — see MSDN. So, you have to use a variable like this:

string replace = "replace1";
WordDocument.Variables[ref replace] = ...;

Strange. Perhaps there's a reason for such an API design.

Also, since the indexer does not define a setter, an assignment won't work. You would have to manipulate the internals of the Variable instance returned by the getter.