Question

我面临一个奇怪的问题。

我创建了一个包含主窗体和辅助窗体的小型WinForms项目。我在代码中的第一个表单中创建了第二个表单，类似于这个：

private void btnOpenForm_Click(object sender, EventArgs e)
{
    NewForm form = new NewForm(value1, value2);
    form.ShowDialog();
}

当我使用ShowDialog()方法时，程序执行后程序会因Invalid parameter错误而立即失败，而常规Show()方法正常。通过stacktrace，它说我不能使用与新主人相同的形式，但那么我应该如何显示一个模态对话框，从主窗体调用？

主窗口构造函数：

public MainWindow()
{
    InitializeComponent();
}

辅助表单构造函数：

public VectorPlot(Point2D OriginalVector, Point2D RotatedVector)
{
    InitializeComponent();

    _originalVector = OriginalVector;
    _rotatedVector = RotatedVector;
}

主窗口调用辅助窗口：

VectorPlot Plot = new VectorPlot(OriginalVector, ModifiedVector);
Plot.ShowDialog();

绘制事件：

private void VectorPlot_Paint(object sender, PaintEventArgs e)
{
    using (Graphics g = e.Graphics)
    {
        GraphicsContainer container = g.BeginContainer(new RectangleF(0f, 0f, 300f, 300f), new RectangleF(0f, 0f, 300f, 300f), GraphicsUnit.Pixel);
        g.FillRectangle(new SolidBrush(Color.White), new RectangleF(0f, 0f, 300f, 350f));
        g.DrawLine(new Pen(Color.Gray), 150f, 0f, 150f, 300f);
        g.DrawLine(new Pen(Color.Gray), 0f, 150f, 300f, 150f);

        float xOrigVect =  (float)_originalVector.X;
        float yOrigVect = (float)_originalVector.Y;
        float xRotVect = (float)_rotatedVector.X;
        float yRotVect = (float)_rotatedVector.Y;

        xOrigVect = 150f + xOrigVect;
        yOrigVect = 150f - yOrigVect;
        xRotVect = 150f + xRotVect;
        yRotVect = 150f - yRotVect;

        g.DrawLine(new Pen(Color.Blue, 2f), 150f, 150f, xOrigVect, yOrigVect);
        g.DrawLine(new Pen(Color.Red, 2f), 150f, 150f, xRotVect, yRotVect);

        g.DrawString("Legenda: ", new System.Drawing.Font("sans-serif", 8.0f), Brushes.Black, new PointF(0f, 310f));
        g.DrawLine(new Pen(Color.Blue, 2f), 0f, 330f, 10f, 330f);
        g.DrawString("Vetor original", new System.Drawing.Font("sans-serif", 8.0f), Brushes.Black, new PointF(10f, 322f));
        g.DrawLine(new Pen(Color.Red, 2f), 0f, 340f, 10f, 340f);
        g.DrawString("Vetor rotacionado", new System.Drawing.Font("sans-serif", 8.0f), Brushes.Black, new PointF(10f, 332f));
        g.EndContainer(container);
    }
}

堆栈追踪：

System.ArgumentException was unhandled
HResult=-2147024809
Message=Parâmetro inválido.
Source=System.Drawing
StackTrace:
   em System.Drawing.Graphics.get_Clip()
   em System.Drawing.Graphics.GetContextInfo()
   em System.Windows.Forms.Internal.WindowsGraphics.FromGraphics(Graphics g, ApplyGraphicsProperties properties)
   em System.Windows.Forms.WindowsGraphicsWrapper..ctor(IDeviceContext idc, TextFormatFlags flags)
   em System.Windows.Forms.VisualStyles.VisualStyleRenderer.DrawBackground(IDeviceContext dc, Rectangle bounds)
   em System.Windows.Forms.Form.OnPaint(PaintEventArgs e)
   em System.Windows.Forms.Control.PaintWithErrorHandling(PaintEventArgs e, Int16 layer)
   em System.Windows.Forms.Control.WmPaint(Message& m)
   em System.Windows.Forms.Control.WndProc(Message& m)
   em System.Windows.Forms.ScrollableControl.WndProc(Message& m)
   em System.Windows.Forms.ContainerControl.WndProc(Message& m)
   em System.Windows.Forms.Form.WndProc(Message& m)
   em System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   em System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   em System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
InnerException:

Answer 1

也许您应该在此方法中提供参数。尝试：

form.ShowDialog(this);

Answer 2

如果你没有在form.ShowDialog（）方法中传递参数，这将默认为当前窗口/表单作为所有者。所以你可以试试。

form.ShowDialog(App.OpenForms[0]); // as default form

或

form.ShowDialog(this); // to make the current window as owner for the form.

修改::

Windows（Win32和WinForms.Net）处理此问题的正常方法是等待MessageQueue运行为空，然后处理所有无效的屏幕区域。这是有效的，因为当某些事情发生变化时，通常会变为其他事物（控件）也会发生变化。

以下是您必须为绘制矢量创建新的usercontrol并使用usercontrols paint事件来完成任务的答案。检查下面的代码。

private void button1_Click(object sender, EventArgs e) { Form2 Plot = new Form2(new Point2D(10, 10), new Point2D(100, 100)); Plot.ShowDialog(); } public partial class Form2 : Form { private Point2D _originalVector; private Point2D _rotatedVector; public Form2() { InitializeComponent(); } public Form2(Point2D OriginalVector, Point2D RotatedVector) { InitializeComponent(); _originalVector = OriginalVector; _rotatedVector = RotatedVector; } private void userControl11_Paint(object sender, PaintEventArgs e) { using (Graphics g = e.Graphics) { GraphicsContainer container = g.BeginContainer( new RectangleF(0f, 0f, 300f, 300f) , new RectangleF(0f, 0f, 300f, 300f) , GraphicsUnit.Pixel); g.FillRectangle(new SolidBrush(Color.White), new RectangleF(0f, 0f, 300f, 350f)); g.DrawLine(new Pen(Color.Gray), 150f, 0f, 150f, 300f); g.DrawLine(new Pen(Color.Gray), 0f, 150f, 300f, 150f); float xOrigVect = (float)_originalVector.X; float yOrigVect = (float)_originalVector.Y; float xRotVect = (float)_rotatedVector.X; float yRotVect = (float)_rotatedVector.Y; xOrigVect = 150f + xOrigVect; yOrigVect = 150f - yOrigVect; xRotVect = 150f + xRotVect; yRotVect = 150f - yRotVect; g.DrawLine(new Pen(Color.Blue, 2f), 150f, 150f, xOrigVect, yOrigVect); g.DrawLine(new Pen(Color.Red, 2f), 150f, 150f, xRotVect, yRotVect); g.DrawString("Legenda: ", new System.Drawing.Font("sans-serif", 8.0f), Brushes.Black, new PointF(0f, 310f)); g.DrawLine(new Pen(Color.Blue, 2f), 0f, 330f, 10f, 330f); g.DrawString("Vetor original", new System.Drawing.Font("sans-serif", 8.0f), Brushes.Black, new PointF(10f, 322f)); g.DrawLine(new Pen(Color.Red, 2f), 0f, 340f, 10f, 340f); g.DrawString("Vetor rotacionado", new System.Drawing.Font("sans-serif", 8.0f), Brushes.Black, new PointF(10f, 332f)); g.EndContainer(container); } } }

Answer 3

也许这个？

form.ShowDialog(this);

你可以粘贴堆栈跟踪吗？

Form.ShowDialog（）导致'无效参数'错误

3 个答案: