Using Shader causes triangle to disappear

The following is my rendering code.

Private Sub GameRender()
    GL.Clear(ClearBufferMask.ColorBufferBit + ClearBufferMask.DepthBufferBit)
    GL.ClearColor(Color.SkyBlue)

    GL.UseProgram(theProgram)

    GL.EnableClientState(ArrayCap.VertexArray)
    GL.EnableClientState(ArrayCap.ColorArray)

    GL.BindBuffer(BufferTarget.ArrayBuffer, vertexPositionID)
    GL.DrawArrays(BeginMode.Triangles, 0, 3)

    GL.DisableClientState(ArrayCap.ColorArray)
    GL.DisableClientState(ArrayCap.VertexArray)

    GlControl1.SwapBuffers()
End Sub

This is screenshot without GL.UseProgram(theProgram)

This is screenshot with GL.UseProgram(theProgram)

Here are my shader code that I picked from online tutorial.

Vertex Shader

#version 330
layout(location = 0) in vec4 position;
void main()
{
    gl_Position = position;
}

Fragment Shader

#version 330
out vec4 outputColor;
void main()
{
   outputColor = vec4(1.0f, 1.0f, 1.0f, 1.0f);
}

These are my shader creation code.

    '' Initialize Shader
    Dim shaderList(1) As Integer
    shaderList(0) = CreateShader(ShaderType.VertexShader, strVertexShader)
    shaderList(1) = CreateShader(ShaderType.FragmentShader, strFragShader)

    theProgram = CreateProgram(shaderList)

    GL.DeleteShader(shaderList(0))
    GL.DeleteShader(shaderList(1))

Here are my helper functions

Private Function CreateShader(ByVal shaderType As ShaderType, ByVal code As String)
    Dim shader As Integer = GL.CreateShader(shaderType)
    GL.ShaderSource(shader, code)
    GL.CompileShader(shader)

    Dim status As Integer
    GL.GetShader(shader, ShaderParameter.CompileStatus, status)
    If status = False Then
        MsgBox(GL.GetShaderInfoLog(shader))
    End If

    Return shader
End Function

Private Function CreateProgram(ByVal shaderList() As Integer) As Integer
    Dim program As Integer = GL.CreateProgram()
    For i As Integer = 0 To shaderList.Length - 1
        GL.AttachShader(program, shaderList(i))
    Next
    GL.LinkProgram(program)

    Dim status As Integer
    GL.GetProgram(program, ProgramParameter.LinkStatus, status)
    If status = False Then
        MsgBox(GL.GetProgramInfoLog(program))
    End If

    For i As Integer = 0 To shaderList.Length - 1
        GL.DetachShader(program, shaderList(i))
    Next

    Return program
End Function