Question

程序假设在panel1上绘制形状。这是我的主要表单的代码：

namespace DrawShapes
{
    public partial class Form1 : Form
    {
        List<Shape> myShapeList;
        Shape shape;

        public Form1()
        {
            InitializeComponent();
        }

        public void AddShape(Shape myshape)
        {
            myShapeList.Add(shape);
        }

        public List<Shape> MyShapeList
        {
            get { return myShapeList; }
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            myShapeList = new List<Shape>();
            shape = new Shape();
        }

        private void drawMeButton_Click(object sender, EventArgs e)
        {
            EditShape editShape = new EditShape();
            editShape.Shape = shape;

            if (editShape.ShowDialog() == DialogResult.OK)
            {
                this.shape = editShape.Shape;
                myShapeList.Add(shape);
                panel1.Invalidate();
            }
            editShape.Dispose();
        }

        private void panel1_Paint(object sender, PaintEventArgs e)
        {
            int panelWidth = panel1.ClientRectangle.Width;
            int panelHeight = panel1.ClientRectangle.Height;

            Pen penLine = new Pen(Color.Blue, 1);

            Graphics g = e.Graphics;
            if (myShapeList != null)
            {
                foreach (Shape element in myShapeList)
                {
                    label1.Text = element.Width.ToString();
                    g.DrawRectangle(penLine, element.XCordinates, element.XCordinates, 50, 50); 
                }
            }
        } 
    }
}

这是我的编辑形状对话框的代码

namespace DrawShapes
{
    public partial class EditShape : Form
    {
        Shape shape = null;



        public EditShape()
        {
            InitializeComponent();
        }

        public Shape Shape
        {
            get { return shape; }
            set { shape = value; }
        }
        private void button1_Click(object sender, EventArgs e)
        {
            shape.Width = 50;
            shape.Height = 50;
            shape.XCordinates = int.Parse(textBox1.Text);
            shape.YCordinates = int.Parse(textBox2.Text);
            shape.Type = 0;
            DialogResult = DialogResult.OK;

        }
    }
}

我在设置形状对象（从“编辑形状”表单）到myShapeList时遇到问题，由于某种原因，所有属性都设置为0。请帮忙。

Answer 1

问题可能是您的AddShape方法。您似乎每次都添加shape而不是传递给方法的形状（myshape）。

如果你这样做会怎么样？

public void AddShape(Shape myshape)
{
    myShapeList.Add(myshape); // myshapeinstead of shape
}

Answer 2

您似乎并未真正将形状添加到造型列表中。您正在接受myShape，然后尝试添加形状。这应该是一个智能感知错误。

public void AddShape(Shape myshape)
    {
        myShapeList.Add(shape);
    }

编辑：没关系，它不会出现错误，因为你有一个名为shape的成员变量。你为所有东西得到零，因为它调用了形状的默认构造函数。

Answer 3

最大的问题在于您对编辑表单的调用。您正在向列表添加相同的对象引用。因此，当您在编辑表单中修改引用时，您将添加到列表中的所有元素更改为最新调用中设置的输入

将您的代码更改为

private void drawMeButton_Click(object sender, EventArgs e)
{
    using(EditShape editShape = new EditShape())
    {
        // Here, create a new instance of a Shape and edit it....
        editShape.Shape = new Shape();
        if (editShape.ShowDialog() == DialogResult.OK)
        {
            // Add the new instance to the list, not the same instance
            // declared globally. (and, at this point, useless)
            myShapeList.Add(editShape.Shape);
            panel1.Invalidate();
        }
        // The using blocks makes this call superflous
        // editShape.Dispose();
    }
}

然后不清楚何时调用方法AddShape（Shape myshape），但很明显你在该方法中有拼写错误

Answer 4

我发现了我的错误。我用错误的参数创建了新的事件处理程序。因此，从未通过我的对话框确定按钮传递的信息从未正确分配。愚蠢的错误。谢谢你们。

c＃List.Add（）无法添加正确的值

4 个答案: