FdoToolbox.DataStoreManager.Controls.SchemaDesigner.ValueConstraintDialog.GetConstraint C# (CSharp) Method

        public static OSGeo.FDO.Schema.PropertyValueConstraint GetConstraint()
        {
            ValueConstraintDialog dlg = new ValueConstraintDialog();
            if (dlg.ShowDialog() == DialogResult.OK)
            {
                return dlg.Constraint;
            }
            return null;
        }

 private void btnEditConstraint_Click(object sender, EventArgs e)
 {
     if (_context.IsConnected)
     {
         var constraint = _dp.ValueConstraint;
         if (constraint == null)
         {
             constraint = ValueConstraintDialog.GetConstraint(_context.Connection);
             if (constraint != null)
             {
                 _dp.ValueConstraint = constraint;
             }
         }
         else
         {
             constraint = ValueConstraintDialog.GetConstraint(constraint, _context.Connection);
             if (constraint != null)
             {
                 _dp.ValueConstraint = constraint;
             }
         }
     }
     else
     {
         var constraint = _dp.ValueConstraint;
         if (constraint == null)
         {
             constraint = ValueConstraintDialog.GetConstraint();
             if (constraint != null)
             {
                 _dp.ValueConstraint = constraint;
             }
         }
         else
         {
             constraint = ValueConstraintDialog.GetConstraint(constraint);
             if (constraint != null)
             {
                 _dp.ValueConstraint = constraint;
             }
         }
     }
 }