Hi All, Iam new to Win32 programming. I am developing GUI to read some channels. Iam able to generate the GUI with Seperate read/write Buttons for each Channel. Iam able to read/write the channels using those buttons. So I kept one single button for Reading and Single button for Writing the Channels. when I click the Single Buttons for reading and writing I am able to read/write to the channels. To achieve this, I have used WM_COMMAND Message i.e in a for loop I use the SendMessage() funtion to generate the button click for each Channels. (make a resemblence of clicking the Seperate Button for each channel.) I went to this approach because My main thread will be listening on the Serial Port for Response . Once the response comes I will generate the next WM_COMMAND message. Here Comes my issue. The GUI window which is used to read/write the channels is updated,when the Single read/write button is clicked only after all the channels are read/write. But I want the GUI to get updated as soon as one channel data is read and so on. Thanks in Advance. Ramesh