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4209 :: How to call SendMessage API function with WM_GETTEXT message >

• kcvinu (orginal) [2018-09-19T23:02:34+02:00] view original

  Hi, I am trying to get text from a textbox. THis is my code. I dont know how to write the stringBuffer part.

  proc getControlText*(chHwnd : HWND) : string =
      var bufferSize : int32
      bufferSize = SendMessage(chHwnd, WM_GETTEXTLENGTH, 0, 0)
      var strBuffer : # What to write here ?
      echo SendMessage(chHwnd,WM_GETTEXT, cast[WPARAM](bufferSize), cast[LPARAM]( strBuffer) )
      result = strBuffer
  Run

  Please help me. Thanks in advance.

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• Ward (orginal) [2018-09-20T10:28:19+02:00] view original

  Take a look at https://khchen.github.io/winim/winstr.html#T.t,string

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• Trustable (orginal) [2018-09-20T12:09:10+02:00] view original

  You can take a look on the WinAPI function GetWindowText() and the implementation of NiGui.

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• kcvinu (orginal) [2018-09-20T14:10:41+02:00] view original

  I found a solution last night and i added a reply to this thread but i dont know, it is not here for unknown reason. I think a network problem. By the way, i tried a lot of possibilities and when tried with LPWSTR, voila ! it worked. This is the solution.

  var stringBuffer : LPWSTR = ""
  Run

  Thats it. Thanks for the replys.

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• kcvinu (orginal) [2018-09-20T14:14:49+02:00] view original

  @Ward, Thanks for the reply. The code in the link looks Chinese to me. May be because of my ignorance about "templates" and "|" sign.

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• kcvinu (orginal) [2018-09-20T14:19:00+02:00] view original

  @Trustable, Thanks a lot for the link. I am using winim for my hobby project. But its very helpful to understand the code better. In this library, they are using nim data types in win api functions. But in winim, we need to cast everything to win api types.

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• Ward (orginal) [2018-09-20T14:39:43+02:00] view original

  Your solution is wrong. You stringBuffer may not have the enough space to store the string. You must alloc the buffer to ensure it have enough space. For example: var stringBuffer = T(bufferSize)

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