I'm trying to render a square in SlimDX.
Code:

public class Square
{
public Buffer vertexBuffer;
public Square(Vector3 origin, float edge, Device device)
{
DataStream Vertices;
Vertices = new DataStream(12 * 5, true, true);
Vertices.Write(new Vector3(1, 1, 0));
Vertices.Write(new Vector3(-1, 1, 0));
Vertices.Write(new Vector3(-1, -1, 0));
Vertices.Write(new Vector3(1, -1, 0));
Vertices.Write(new Vector3(1, 1, 0));
Vertices.Position = 0;
vertexBuffer = new Buffer(device, Vertices, 12 * 5, ResourceUsage.Default, BindFlags.VertexBuffer, CpuAccessFlags.None, ResourceOptionFlags.None, 0);
Vertices.Close();
}
public void Draw(Device device)
{
device.ImmediateContext.InputAssembler.PrimitiveTopology = PrimitiveTopology.LineStrip;
device.ImmediateContext.InputAssembler.SetVertexBuffers(0, new VertexBufferBinding(vertexBuffer, 12, 0));
device.ImmediateContext.Draw(4, 0);
}
}

However, only first four elements of DataStream Vertices are rendered. For square, it corresponds to 3 lines. I tried other PrimitiveTopology like TriangleList, TriangleStrip or PointList, they all behave the same - load only first 4 vertices no matter how big original DataStream is. I remember to create vertexBuffer with the same size as DataStream and tried to make it bigger as well.

Draw(int vertexCount, int startVertexLocation)

... vertex count, not primitive count.

it was 1 am, now it's clear. Thx anyway