c# - GetDeviceCaps 技术

Question

我有一个控件，我想在表单和打印时以不同的方式绘制它。这是我做的方式:

private void printDocument1_PrintPage(object sender, System.Drawing.Printing.PrintPageEventArgs e)
    {
        Rectangle rect = myControl.ClientRectangle;
        myControl.Render(e.Graphics, rect);
        e.HasMorePages = false;
    }

在渲染函数中

public void Render(Graphics g, Rectangle rect) {
      DeviceCapTechnology dct = (DeviceCapTechnology)GetDeviceCaps(hDC, (int)DeviceCap.TECHNOLOGY);
      if((dct & DeviceCapTechnoloy.DT_RASPRINTER) == DeviceCapTechnoloy.DT_RASPRINTER) {
           //logic for print to printer
      } else {
           //normal logic
      }
}
public enum DeviceCapTechnology
    {
        DT_PLOTTER = 0, //Vector plotter
        DT_RASDISPLAY = 2, //Raster display
        DT_RASPRINTER = 4, //Raster printer
        DT_RASCAMERA = 6, //Raster camera
        DT_CHARSTREAM = 8, //Character stream
        DT_METAFILE = 10, //Metafile
        DT_DISPFILE = 12 //Display file
    }

但是当 PrintDocumentDialog 显示时，测试结果总是 DT_RASDISPLAY 而不是我期望的 DT_RASPRINTER。

那么正确的做法是什么？

谢谢

Answer 1

你的 DeviceCapTechnology 枚举是错误的

/* Device Technologies */
#define DT_PLOTTER          0   /* Vector plotter                   */
#define DT_RASDISPLAY       1   /* Raster display                   */
#define DT_RASPRINTER       2   /* Raster printer                   */
#define DT_RASCAMERA        3   /* Raster camera                    */
#define DT_CHARSTREAM       4   /* Character-stream, PLP            */
#define DT_METAFILE         5   /* Metafile, VDM                    */
#define DT_DISPFILE         6   /* Display-file                     */