空引用异常未处理？

本文介绍了空引用异常未处理？的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述 29岁程序员，3月因学历无情被辞！ 我收到此警告对象引用未设置为对象的实例 此行i got this warning "Object reference not set to an instance of an object"on this line引用：位图直方图=新位图（256,256，PixelFormat.Format24bppRgb）;Bitmap histogram = new Bitmap(256, 256, PixelFormat.Format24bppRgb); 我尝试过： b $ bWhat I have tried:unsafe public static Bitmap CreateHistogram(Bitmap source, bool isGray) { if (source.PixelFormat == PixelFormat.Format24bppRgb) { Bitmap histogram = new Bitmap(256, 256, PixelFormat.Format24bppRgb); BitmapData data = source.LockBits(new Rectangle(0, 0, source.Width, source.Height), ImageLockMode.ReadWrite, source.PixelFormat); byte* p = (byte*)data.Scan0; int offset = data.Stride - source.Width * 3; if (isGray == false) { for (int hang = 0; hang < source.Height; hang++) { for (int cot = 0; cot < source.Width; cot++) { //0.21 R + 0.72 G + 0.07 B byte t = (byte)(0.07f * p[0] + 0.72f * p[1] + 0.21 * p[2]); p[0] = p[1] = p[2] = t; p += 3; } p += offset; } p = (byte*)data.Scan0; } int[] count = new int[256]; int max = 0; for (int hang = 0; hang < source.Height; hang++) { for (int cot = 0; cot < source.Width; cot++) { count[p[0]]++; if (count[p[0]] > max) max = count[p[0]]; p += 3; } p += offset; } source.UnlockBits(data); // max 255 // x => x*255/max for (int i = 0; i < 256; i++) count[i] = (int)(count[i] * (histogram.Height - 1) * 1f / max * 1f); data = histogram.LockBits(new Rectangle(0, 0, histogram.Width, histogram.Height), ImageLockMode.ReadWrite, histogram.PixelFormat); p = (byte*)data.Scan0; offset = data.Stride - histogram.Width * 3; for (int cot = 0; cot < histogram.Width; cot++) { for (int hang = 0; hang < histogram.Height; hang++) { byte value = 255; if (hang <= (histogram.Height - count[cot])) value = 255; else value = 0; p[indexOf(hang, cot, data.Stride)] = value; p[indexOf(hang, cot, data.Stride) + 1] = value; p[indexOf(hang, cot, data.Stride) + 2] = value; } } histogram.UnlockBits(data); return histogram; } else { MessageBox.Show("PixelFormat: " + source.PixelFormat); return source; } }推荐答案 这篇关于空引用异常未处理？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！ 上岸，阿里云！