鼠标事件不会在winforms中更新相机旋转

我的应用程序有一个自定义面板，用于在WinForm中显示XNA屏幕。我目前已经展示了一个没有问题的测试模型，现在正在研究相机的移动。我的相机是一个自由相机（不一定要看任何特定的目标），但我一直很难让鼠标更新相机在自己轴上的偏航和俯仰。我想我的更新方法可能有问题，但事实并非如此，因为相机使用KeyboardState前后更新。但我不知道为什么MouseState不起作用。

FreeCamera.cs

using XNAButtonState = Microsoft.Xna.Framework.Input.ButtonState;
....
MouseState pastMouseState;
private float rotationSpeed_ = 1f / 60f;
private float yaw_, pitch_;
...
private void updateMatrix()
    {
        Matrix rotationMatrix = Matrix.CreateRotationX(pitch_) *
                                Matrix.CreateRotationY(yaw_);
        Vector3 forward = new Vector3(0, 0, 1);
        forward = Vector3.Transform(forward, rotationMatrix);
        viewMatrix_ = Matrix.CreateLookAt(Position, Position + forward, Up);
        projectionMatrix_ = Matrix.CreatePerspectiveFieldOfView(
            MathHelper.PiOver4, 16.0f / 9.0f, 0.1f, 100000.0f);
    }
 private void cameraInput()
    {
        KeyboardState keyboardState = Keyboard.GetState(); <-- updates
        currentMouseState = Mouse.GetState();              <-- not updating
        if (currentMouse.LeftButton == XNAButtonState.Pressed)         
            pitch_ -= rotationSpeed_;
        if (keyboardState.IsKeyDown(Keys.W))
            move(1);
        if (keyboardState.IsKeyDown(Keys.S))
            move(-1);
        pastMouseState = currentMouseState;
     }

public void update()
    {
        cameraInput();
        updateMatrix();

Mouse.WindowHandle = this.Handle;