LINQ to Entities - How to retrieve a data and use it as a variable in the whole project

If LastName and FirstName are being input (in that order) to TextBox1 then, assuming they are separated by a space or spaces, you can split them up as follows:

string[] items = TextBox1.Text.Trim().Split(new char[]{' '}, StringSplitOptions.RemoveEmptyEntries);
string lastName = items[0];
string firstName = items[1];

The second argument to the Split method deals with the possibility that there might be multiple spaces separating the last and first names.

If the ID column is used to link the Employee and Tasks tables, you should then be able to retrieve the related TaskName and place it in a global variable as follows:

// create a class to contain global variables if you don't already have one

static class Global
{
    public static string Task {get; set;}
}


// within some method in some other class

// insert above code to get last and first names

using (LINQtoEntitiesEntities MyEntities = new LINQtoEntitiesEntities())
{
   ObjectQuery Employee = MyEntities.Employee;
   ObjectQuery Tasks = MyEntities.Tasks;
   Global.Task = (from e in Employee where e.LastName == lastName && e.FirstName == firstName join t in Tasks on e.ID equals t.ID select t.TaskName).FirstOrDefault();
}


// retrieve global variable from elsewhere:

if (Global.Task != null)
{
   // do something with Global.Task
}