GetDlgItemText为什么只能获取部分数据？

[亚细亚]

char szText[128]={0};
GetDlgItemText(hwnd,IDC_SENDTXT,szText,sizeof(szText));
在文本框IDC_SENDTXT中输入如下数据：
01 03 38 cf f7 a4 41 29 5c 0f 3f 00 00 00 00 00 00 80 3f 00 00 00 00 00 00 20 41 2c 18 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 7d bb
结果发现通过GetDlgItemText中的szText所得到的数据为：
01 03 38 cf f7 a4 41 29 5c 0f 3f 00 00 00 00 00 00 80 3f 00 00 00 00 00 00 20 41 2c 18 00 00 00 00 00 00 00 00 00 00 00 00 00 0
这是什么原因？

[worldy]

LZ你自己数数01 03 38 cf f7 a4 41 29 5c 0f 3f 00 00 00 00 00 00 80 3f 00 00 00 00 00 00 20 41 2c 18 00 00 00 00 00 00 00 00 00 00 00 00 00 0 这堆数据含空格，有多少字节了?