其实就是调用系统api而已，原型是：
BOOL WINAPI SystemParametersInfo( __in UINT uiAction, __in UINT uiParam, __in_out PVOID pvParam, __in UINT fWinIni);
1using System.Runtime.InteropServices;
//////声明下
2[DllImport("user32.dll", EntryPoint = "SystemParametersInfoA")]
3static extern Int32 SystemParametersInfo(Int32 uAction, Int32 uParam, string lpvParam, Int32 fuWinIni);//////lpvParam要设置成string
4private const int SPI_SETDESKWALLPAPER = 20;
5
6SystemParametersInfo(SPI_SETDESKWALLPAPER, 0, filename, 1);/////调用，filename为图片地址，最后一个参数需要为1，0的话在重启后就变回原来的了
using System.Runtime.InteropServices;//////声明下
2
[DllImport("user32.dll", EntryPoint = "SystemParametersInfoA")]3
static extern Int32 SystemParametersInfo(Int32 uAction, Int32 uParam, string lpvParam, Int32 fuWinIni);//////lpvParam要设置成string4
private const int SPI_SETDESKWALLPAPER = 20;5
6
SystemParametersInfo(SPI_SETDESKWALLPAPER, 0, filename, 1);/////调用，filename为图片地址，最后一个参数需要为1，0的话在重启后就变回原来的了至少vista下成功了。