IWCombobox OnAsyncChange code is as follows:

 procedure TfmBM. TfmXLSelect1IWComboBox1AsyncChange (Sender: TObject; 
EventParams: TStringList); 
The begin 
UID:=TfmXLSelect1 IWComboBox1. Items. ValueFromIndex [TfmXLSelect1. IWComboBox1. ItemIndex]; 
DmAdd. ShowXl (UID); 
end; 

DmAdd Clientdataset data to modify the code is as follows:

 procedure TdmAdd. ShowXl (iXLUID: string). 
The begin 
With cdsBM_Edit do 
If (iXLUID<> ") then 
The begin 
If (FieldByName (' RY_XL_UID). AsString<> Then iXLUID) 
The begin 
Edit; 
FieldValues [' RY_XL_UID] :=iXLUID; 
Post; 
End 
Else the Locate (' RY_XL_UID iXLUID, []); 
end; 
end; 

First click IWCombobox OnAsyncChange is effective and the result is all right but later events failure
Annotation

 Edit; 
FieldValues [' RY_XL_UID] :=iXLUID; 
Post; 

after normal again this is why urgent urgent!!!!!!