Find a window control at a point on the screen

michael447887

How do I find a control (such as a text box) from a window running in a separate process based on an X,Y screen coordinate

nobugz

Use the WindowFromPoint() API function. Visit www.pinvoke.net for the necessary P/Invoke declarations.

michael

Thanks, that's what I was looking for. I looked at the pinvoke.net website, and I found the function "GetDlgItemText￣ but I can't get it to work. Does anyone know what needs to be passed into the parameters I've searched on other sites for it also, but I still can't figure it out.

nobugz

The string pointer must point to a buffer that's valid in the virtual memory space of the process that owns the window. You can't pass yours. Bypassing this issue is not easy, you need to VirtualAllocEx() a buffer, then ReadProcessMemory() the buffer content.

michael

Can you give me more details on how to do that I am really confused.

nobugz

A Google query for these API functions can be useful. This was the second hit.

michael

Thank you for your help. I have figured it out for the most part, but here is my new problem: I am only able to get text out of text boxes running in the same process. I can, however, get text from labels or other controls in other processes. How can I get text out of text boxes in other processes

It also appears that I can only get information about the programs I have written in VB.NET using VS2003. Does anyone have any ideas why that would be

nobugz

Use GetWindowText().

michael

That let's me get only the values of text boxes if they were filled in to start with. If I fill in the data later, or if it changes, the changes wont show when i use GetWindowText(). I looked on pinvoke.net, and I couldn't find a refresh function or anything that looked helpful.

nobugz

Not sure I follow. Using GetWindowText() *after* the textbox has updated its content returns the old string

michael

right. If the text box is originally empty, and I type something into it, GetWindowText() will return an empty string. If the original value is 4, and I change it to 5, it will return 4.