Basic Word Mail Merge functionality with C#.NET - given Data File and Merge Doc

Mail Merge uses a document to hold the pattern for the result documents. It is quite  easy to set it up manually using the Mail merge wizard which is built in to the Word user interface (Tools/Letters and Mailings). This requires that the datasource be specified and then the merge fields be placed where needed. The merge fields point to data source fields by name. If the main document, as it is called, is saved, the datasource link is saved with it.

Programatically you can use the OpenDataSource method to link a particular data source to the document. Hopefully it will have the same field names as the datasource that document was designed for.

A document object has a Mailmerge Property which holds the Datasource object and has an Execute method to actually run the merge.

I don't use C#, but if you can understand VB, the Help in Word's VBA editor should be able to help you more.

Thanks GrahamSkan,

I've got it working with one small problem.  My OnClick event is referencing the correct files (template.doc, and datafile.xls); however, when it executes the merge I get a prompt asking me to "Select Table." My xls only has one worksheet so the worksheet is selected and a checkbox is checked that indicate that the first row is my header row.

I click "Ok" and the merge executes perfectly.

I just need to figure out how to specify the header row is my first record in the XLS.

Here's the code I've been working with.
            // Create an instance of Word  and make it visible.
            wrdApp = new Word.Application();
            wrdApp.Visible = true;
            Word.Document myMergeDocument;

            string strFileName = "c:\\template.doc";
            string strDataFile = "c:\\datafile.xls";

            object filename = strFileName;
            object objTrue = true;
            object objFalse = false;
            object objMiss = Type.Missing;


            //Open merge document
            myMergeDocument = wrdApp.Documents.Open(ref filename, ref objMiss, ref objMiss, ref objMiss, ref objMiss, ref objMiss, ref objMiss, ref objMiss, ref objMiss, ref objMiss, ref objMiss, ref objMiss, ref objMiss, ref objMiss, ref objMiss, ref objMiss);
            myMergeDocument.Select();

           

            //Open the data source
            object source = strDataFile;
            object format = Word.WdOpenFormat.wdOpenFormatAuto;
            myMergeDocument.MailMerge.OpenDataSource(strDataFile, ref format, ref objFalse, ref objMiss, ref objTrue, ref objFalse, ref objMiss, ref objMiss, ref objMiss, ref objMiss, ref objMiss, ref objMiss, ref objMiss, ref objMiss, ref objMiss, ref objMiss);

            //Perform Merge
            myMergeDocument.MailMerge.Destination = Word.WdMailMergeDestination.wdSendToNewDocument;

           
            myMergeDocument.MailMerge.SuppressBlankLines = true;
            myMergeDocument.MailMerge.DataSource.FirstRecord = (int)Word.WdMailMergeDefaultRecord.wdDefaultFirstRecord;
            myMergeDocument.MailMerge.DataSource.LastRecord = (int)Word.WdMailMergeDefaultRecord.wdDefaultLastRecord;
            myMergeDocument.MailMerge.Execute(ref objFalse);

Thank you!