I need to write an application with Silverlight 4 and need to show images like wrapped on cylinder. I need some HLSL code, as I wont to do that with Effects of Silverlight.<
This seems to be the effect you want, you may wish to change the 0.2 value to increase or decrease the effect or make this adjustable in your shader but that's a simple change to do. I'd recommend Shazzam if your not using it for writing shaders for WPF or Silverlight.
sampler2D input : register(s0);
float4 main(float2 uv : TEXCOORD) : COLOR
{
float y = uv.y+(sin(uv.x*3.14) * lerp(-1,1,uv.y) * 0.2);
if(y < 0 || y > 1)
return float4(0,0,0,0);
else
return tex2D(input,float2(uv.x,y));
}