Error while inserting a record

I am getting error like this

String or binary data would be truncated.
The statement has been terminated.

here is the my code

in DAL.cs
 public bool insertemployee(Cmp c)
        {
            EmployeesDataContext db = new EmployeesDataContext();
            Employee emp=new Employee();
            emp.empid = c.empid;
            emp.empname = c.empname;
            emp.salary = c.salary;
            emp.hiredate = c.hiredate;
            db.Employees.InsertOnSubmit(emp);
            db.SubmitChanges();
            return true;
        }

in Default.aspx.cs
  protected void btnsubmit_Click(object sender, EventArgs e)
        {
            Cmp c = new Cmp();
            Employe emp = new Employe();
            c.empid = Convert.ToInt32(txtempid.Text);
            c.empname = txtempname.ToString();
            c.hiredate = Convert.ToDateTime(txthiredate.Text);
            c.salary = Convert.ToInt32(txtsalary.Text);
            emp.insertemployee(c);
        }