I searched a lot for this problem but i did not find any clear post about that.
I do databinding with this command:
userControl1.DataBindings.Add( "Text",dt,"DM" );
I also put dt for datagridview datasource.
this work for usual controls but not for usercontrols.
Now the Text of the usercontrol does not change if i select different rows of datagridview and it is always empty.
I think this problem is simple.Should I use INotifyPropertyChanged?