display sorting triangle in ListView column header

Posted on 1998-08-16
Last Modified: 2010-04-03
How can I display in a ListView column header a triangle that shows after which column are sorted the items, and in which direction (like in the Microsoft Internet Mail and News)?
Question by:biroadam
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Accepted Solution

erajoj earned 50 total points
ID: 1336098
You could do something like this:

  ...ComCtrls, Commctrl;

  MyBMP : TBitmap;
  hditem: THDItem;

  MyBMP := TBitmap.Create;
  with MyBMP do begin
    Canvas.Brush.Color := clBtnFace;
    Width  := 10;
    Height := 10;
// down...
//  up...
//  Canvas.Polyline([Point(0,8),Point(4,0),Point(8,8),Point(0,8)]);


  hditem.Mask := HDI_FORMAT;
  Header_GetItem( GetDlgItem( ListView1.Handle, 0 ), 1, hditem );
  hditem.Mask := HDI_BITMAP or HDI_FORMAT;
  hditem.fmt  := hditem.fmt or HDF_BITMAP;
  hditem.hbm := MyBMP.Handle;
  Header_SetItem( GetDlgItem( ListView1.Handle, 0 ), 1, hditem );

/// John


Expert Comment

ID: 1336099
Did you check it? It doesn't seem to work.

Author Comment

ID: 1336100
 Thank you, it was a good answer.

  I have two further questions:

  1. How can I move the bitmap on the RIGHT side of the column header’s caption (the bitmap generated by your code is on the left side)?

  2. How can I resolve the transparency problem for this bitmap? I must have a triangle on a clButtonFace background, so I have two choises: A. making a procedure which calls the CreateGrayMappedBmp function every time the system colors changes, or B. I have a transparent color.

  I couldn’t use the solution B because setting my bitmap’s Transparency, TransparentColor and TransparentMode properties, the transparency didn’t work on the column header.

Expert Comment

ID: 1336101
Does it work on NT4?
Does it work when the listview is not on the main form?

If yes, can you please send me the sample code?


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