C＃位圖圖片框無法正常工作

Question

我試圖做一些梯度&預覽它在PictureBox不保存，但它似乎不工作：

 if (isChanged == true) 
     { 
       re = new Rectangle(0, 0, int.Parse(textBox5.Text), int.Parse(textBox4.Text)); 
       currectBrush = new System.Drawing.Drawing2D.LinearGradientBrush(re, System.Drawing.ColorTranslator.FromHtml("#FC00FF"), System.Drawing.ColorTranslator.FromHtml("#00DBDE"), -45f); ; 
       bitmap = new Bitmap(int.Parse(textBox5.Text), int.Parse(textBox4.Text)); 
       using (bitmap) 
       using (var graphics = Graphics.FromImage(bitmap)) 
       { 
        currectBrush = new System.Drawing.Drawing2D.LinearGradientBrush(re, System.Drawing.ColorTranslator.FromHtml(textBox1.Text), System.Drawing.ColorTranslator.FromHtml(textBox2.Text), int.Parse(textBox3.Text)); 

        graphics.FillRectangle(currectBrush, re); 
        pictureBox1.Image = bitmap; 

       } 
       isChanged = false; 
     } 

而且這是圖片框的樣子運行此之後部分代碼：

Answer 1

刪除此行，因爲其配置的資源

using (bitmap)