Remove/Edit word office builtindocumentproperties in c#

Question

Please need your help regarding this code. I am wrting a code in c# that can will clear a word document built in property, and also replace it with a provided replacement where provided. Base on the example i found online in microsft support website http://support.microsoft.com/kb/303296 , my code is alright and suppose to work as i dont get any compile error as well. but is not doing what i ask it to do as i dont get any result. Please guys , will really appreciate it if some one will help me with an ulternative or point out my error so that the weeks i spent will ruin in vain. Thanks you as you help. Below is my code.

 private void execute_Click(object sender, EventArgs e)
        {
             Word.Application wapp; 
             Word.Document dc = new Word.Document() ;
 Object bSaveChanges = false;
           string chosen_file = "";
           chosen_file = openFD.FileName;
           textBox1.Text = (chosen_file);
           var filter = Path.GetExtension(chosen_file);

           object Filename = chosen_file.ToString();
           if (filter == ".doc" || filter == ".docx")
           {
               wapp = new Word.Application();
               wapp.Visible = true;
               docword = wapp.Documents.Add(ref Filename, ref missing, ref missing, ref missing);

               object _BuiltInProperties = docword.BuiltInDocumentProperties;
                Type typeDocBuiltInProps = _BuiltInProperties.GetType();

                 removeproperty(_BuiltInProperties, typeDocBuiltInProps);// pass parameter
                 docword.Close(ref bSaveChanges, ref missing, ref missing);
                 wapp.Quit(ref bSaveChanges, ref missing, ref missing);
           }
  }

 private void removeproperty(object _BuiltInProperties, Type typeDocBuiltInProps)
        {

            string subjectprop = "Subject";
            string subjectValue = "";
            string companyprop = "Company";
            string companyvalue = txtcompany.Text;

             if (clearsubject.Checked == true)
            {
                try
                {
                    Object Subjectprop = typeDocBuiltInProps.InvokeMember("Item", BindingFlags.Default | BindingFlags.GetProperty, null, _BuiltInProperties, new object[] { "Subject" });
                    Type typeSubjectprop = Subjectprop.GetType();

                    typeSubjectprop.InvokeMember("Item", BindingFlags.Default | BindingFlags.SetProperty, null, Subjectprop, new object[] { subjectprop, subjectValue  });

                }
                catch (COMException)
                {

                }

            }

       if (resetcompany.Checked == true)
            {
                try
                {
                  Object Companyprop = typeDocBuiltInProps.InvokeMember("Item", BindingFlags.Default | BindingFlags.GetProperty, null, _BuiltInProperties, new object[] { "Company" });
                    Type typeCompanyprop = Companyprop.GetType();
                    typeCompanyprop.InvokeMember("Item",
                               BindingFlags.Default |
                               BindingFlags.SetProperty,
                               null, Companyprop,
                               new object[] { companyprop, companyvalue });


                }
                 catch (COMException)
                {

                }


}

Answer 1

1) Add reference to Microsoft.CSharp.

2) Get BuiltInDocumentProperties:

private void LoadMetadata(Document Doc) {
  this.Title.Text = Doc.BuiltInDocumentProperties["Title"].Value;
  this.Subject.Text = Doc.BuiltInDocumentProperties["Subject"].Value;
  this.Category.Text = Doc.BuiltInDocumentProperties["Category"].Value;
  this.Keywords.Text = Doc.BuiltInDocumentProperties["Keywords"].Value;
  this.Author.Text = Doc.BuiltInDocumentProperties["Author"].Value;
  this.Comments.Text = Doc.BuiltInDocumentProperties["Comments"].Value;
}

3) Set new values:

private void SaveMetadata(Document Doc) {
  Doc.BuiltInDocumentProperties["Title"].Value = this.Title.Text;
  Doc.BuiltInDocumentProperties["Subject"].Value = this.Subject.Text;
  Doc.BuiltInDocumentProperties["Category"].Value = this.Category.Text;
  Doc.BuiltInDocumentProperties["Keywords"].Value = this.Keywords.Text;
  Doc.BuiltInDocumentProperties["Author"].Value = this.Author.Text;
  Doc.BuiltInDocumentProperties["Comments"].Value = this.Comments.Text;
}

Answer 2

As found here, you can change word properties by name like so:

void SetWordDocumentPropertyValue(Word.Document document, string propertyName, string propertyValue)
{
  object builtInProperties = document.BuiltInDocumentProperties;
  Type builtInPropertiesType = builtInProperties.GetType();
  object property = builtInPropertiesType.InvokeMember("Item", System.Reflection.BindingFlags.GetProperty, null, builtInProperties, new object[] { propertyName });
  Type propertyType = property.GetType();
  propertyType.InvokeMember("Value", BindingFlags.SetProperty, null, property, new object[] { propertyValue });
  document.UpdateSummaryProperties();
  document.Save();
}

Property names are like "Author", "Last Author", "Title", etc...