小弟又來發問了，因為版上實在是有太多的高手，而且都願意撥冗協助小弟的難題，讓小弟獲益匪淺，今日再來打擾，也希望眾家大姐大哥再相助，先謝啦！ 小弟這回想以最基本的方式叫出JPEG圖檔並顯示，但是不知何故，第一個可以顯示，但是第二個就顯示不出來，但是我去看第二個的寬高資料都是正常的，請高手開釋一下吧，謝啦！ 小弟的程式碼如下： void __fastcall TForm1::Button1Click(TObject *Sender) { OpenDialog1->Filter = "JPEG檔案|*.jpg"; if (OpenDialog1->Execute()) { TMemoryStream *myStream = new TMemoryStream; TJPEGImage *jpg1 = new TJPEGImage(); TJPEGImage *jpg2 = new TJPEGImage(); AnsiString file_name = OpenDialog1->FileName ; AnsiString FileExt = ExtractFileExt(file_name); if (FileExt == ".jpg" || FileExt == ".jpeg") { jpg1->LoadFromFile(file_name); Form1->Canvas->Draw(0,0,jpg1); jpg1->SaveToStream(myStream); myStream->Position = 0; jpg2->LoadFromStream(myStream); Form2->Canvas->Draw(0,0,jpg2); Form2->Show(); delete jpg1; delete jpg2; delete myStream; } } }

You draw before showing the form... swap the 2 lines as: Form2->Show(); Form2->Canvas->Draw(0,0,jpg2); // draw only after showing the form Since the default paint method of the form should clear the image you draw on its canvas.

那麼第一個圖能出來的原因是，原本Form1一開始就會show出來了，所以不用先寫 Form1->Show(); 也可以看到圖囉？

引言: 那麼第一個圖能出來的原因是，原本Form1一開始就會show出來了，所以不用先寫 Form1->Show(); 也可以看到圖囉？

Yes, but a repaint of the form will erase the image. You may want to place a TImage on the form and draw on its canvas. TImage will store the image in an internal bitmap and it can repaint itself.

多謝william大哥的指導！ 我試過了，真的是這樣…