take the value of outArgument in activity to another activity

By this : http://msdn.microsoft.com/en-us/library/dd489442.aspx but the only diffenet that I make the workflow using a XAML file.

I have a qution: i need to pass the value that I got from the user to another activity. I tried to make a variable (output for example )and assiged the value, but the another activity see it like empty. may its dead or reset to the default value after the current activity finishs.

I tried to use OutArgument, but it make runtime error at app.run as the following

"The following errors were encountered while processing the workflow tree: 'workflow1': The private implementation of activity '1: workflow1' has the following validation error: Value for a required activity argument 'Out_arg' was not supplied." And also didn't see it in the next activity like the first case.

[RequiredArgument]
public OutArgument<string> Out_arg { get; set; }

        void OnBookmarkCallback(NativeActivityContext context, Bookmark bookmark, object val)
        {
            Console.WriteLine("im in resume ");
            Console.WriteLine("bookmark1 Name is {0}", (string)val);
            // for the first option that i tried
            output = (string)val;
           //then i tried
            Out_arg.Set(context, (开发者_Go百科string)val);

the xmal file: False 270,2.5 60,75 300,77.5 300,107.5 300,129.5 194.5,129.5 211,61 300,190.5 300,220.5 300,279 200,279 200,22 300,301 300,331 280,331 280,389.5 174.5,389.5 211,61 _ReferenceID0 _ReferenceID1 __ReferenceID2

Can u help me?

Did you create variable in you workflow and assign the Out_arg to it?