如何将"System.Drawing.Image"转换为"System.Drawing.Bitmap"? [英] How to Convert 'System.Drawing.Image' to 'System.Drawing.Bitmap'?

问题描述

GraphicsImage = new Bitmap(Panel1.Width, Panel1.Height, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
openFileDialog1.Filter="JPEG|*.jpg";
GraphicsImage = Image.FromFile(openfiledialog1.FileName);

错误:
Error 1 Cannot implicitly convert type ''System.Drawing.Image'' to ''System.Drawing.Bitmap''. An explicit conversion exists (are you missing a cast?)

ERROR:
Error 1 Cannot implicitly convert type ''System.Drawing.Image'' to ''System.Drawing.Bitmap''. An explicit conversion exists (are you missing a cast?)

推荐答案

您必须使用以下内容更改最后一行

you have to change last line with following

GraphicsImage = (Bitmap)Image.FromFile(openfiledialog1.FileName);

这会更好，因为它们是相同的类型:

This would work better because they are the same type:

Bitmap graphicsImage = new Bitmap(Panel1.Width, Panel1.Height, System.Drawing.Imaging.PixelFormat.Format24bppRgb);

但是没有必要创建它，因为这样做时它会被前面两行覆盖:

But there is no need to create it because it is overwritten 2 lines ahead when doing:

GraphicsImage = Image.FromFile(openfiledialog1.FileName);

祝你好运！

Good luck!

错误消息中的内容完全正确.
您需要将图像投射到位图:

Exactly what the error message said.
You need to cast the Image to a Bitmap:

GraphicsImage = (Bitmap)Image.FromFile(openfiledialog1.FileName);

通过说显式强制转换存在"，表明您必须进行类型强制转换.另一个说法是:

By saying that an "explicit casts exists" you''re hinted that you must do a type cast. Another verions is this:

GraphicsImage = Image.FromFile(openfiledialog1.FileName) as Bitmap;

修改:

如果要使图像适合面板，有两种选择:

1.保持图像的宽高比，您需要进行此调整

Modification:

You have two options if you want to make the image fit into the panel:

1. Keeping the images aspect ratio you need to make this adjustment

panel1.BackgroundImageLayout = ImageLayout.Zoom;

2.在不考虑图像高宽比的情况下，用图像填充整个面板

2. Filling the whole panel with the image disregarding the aspect ratio of the image

panel1.BackgroundImageLayout = ImageLayout.Stretch;

注意！
如果面板的尺寸与图像的尺寸不匹配，解决方案2将使您的图像失真.

最终修改

就这样！

干杯，
曼弗雷德(Manfred)

Caveat!
Solution 2 will leave you with a distorted image if the panel''s dimensions don''t match the dimensions of the image.

End Modification

That''s it!

Cheers,
Manfred

这篇关于如何将"System.Drawing.Image"转换为"System.Drawing.Bitmap"?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！