Question

i have the following function in Form1 and would like to call it when a button in Form2 is clicked.

   public object GetStudents()
    {
        using (var DB = new myView1())
        {
            var studentList = (from s in DB.View123
                            select new { s.StudentName, s.StudentNumber, s.ClassName, s.StreamName, s.ParentName }).ToList();
            dataGridViewStudents.DataSource = students;
            return students.ToList();
        }
    }

Above function is in Form1, how do i call it from a button_Click event in Form2. This is some thing simple in VB.NET

Answer 1

It’s also simple in C#. You just need an instance of Form1 and then you can call this method on that instance.

However, there’s a better approach. This code doesn’t actually belong on a form. Forms are for UI interactions, not for business logic and data access. You’re better off moving this code to a common location which would be accessed by both forms.

Create a data access class. Something like this:

public class StudentRepository
{
    public static object GetStudents()
    {
        using (var DB = new myView1())
        {
            var studentList = (from s in DB.View123
                        select new { s.StudentName, s.StudentNumber, s.ClassName, s.StreamName, s.ParentName }).ToList();
            dataGridViewStudents.DataSource = students;
            return students.ToList();
        }
    }
}

Notice also that the method is now static which means it doesn’t need an instance to be called. (This is like the Shared keyword in VB.) So your forms can just call:

var students = StudentRepository.GetStudents();

Another thing you’ll want to fix, although it’s outside the scope of this question, is that return type. object isn’t very specific. You should have a Student class and that method should return IList<Student>. Something like this:

public class Student
{
    public string StudentName { get; set; }
    public int StudentNumber { get; set; }
    public string ClassName { get; set; }
    public string StreamName { get; set; }
    public string ParentName { get; set; }
}

and:

public class StudentRepository
{
    public static IList<Student> GetStudents()
    {
        using (var DB = new myView1())
        {
            var studentList = (from s in DB.View123
                        select new Student { StudentName = s.StudentName, StudentNumber = s.StudentNumber, ClassName = s.ClassName, StreamName = s.StreamName, ParentName = s.ParentName }).ToList();
            dataGridViewStudents.DataSource = students;
            return students.ToList();
        }
    }
}

I made some assumptions about the types for the fields, you should be able to correct those if they’re wrong. You might even want it to return an IEnumerable<Student> instead of IList<Student> if it’s an unchanging result (that is, if it’s just an enumeration of students and not a list to be added to, removed from, etc.).

There’s a lot more you can do here, such as having an object for other data elements such as Class (which might need a different name, just to be clean), Parent, Stream, etc. (Come to think of it, several of these might need better names. Your variable naming in general needs a little work. Things like Form1 or myView1 don’t convey intent very well.)