C#，如何使用 savefiledialog 为类绘画程序保存图片

Question

我尝试了很多方法，包括位图转换等。 这是我的代码。会喜欢它，有人会向我解释如何保存它以及为什么。谢谢！

public partial class Form1 : Form
{
    Graphics G;
    Pen myPen = new Pen(Color.Black);
    Point sp = new Point(0, 0);
    Point ep = new Point(0, 0);
    int ctrl = 0;

    public Form1()
    {
        InitializeComponent();
    }

    private void panel1_Paint(object sender, PaintEventArgs e)
    {

    }

    private void panel1_MouseDown(object sender, MouseEventArgs e)
    {
        sp = e.Location;
        if(e.Button == MouseButtons.Left)
        {
            ctrl = 1;
        }
    }

    private void panel1_MouseUp(object sender, MouseEventArgs e)
    {
        ctrl = 0;
    }

    private void panel1_MouseMove(object sender, MouseEventArgs e)
    {
        if(ctrl == 1)
        {
            ep = e.Location;
            G = panel1.CreateGraphics();
            G.DrawLine(myPen, sp, ep);
        }
        sp = ep;
    }

    private void button1_Click(object sender, EventArgs e)
    {
        colorDialog1.ShowDialog();
        myPen.Color = colorDialog1.Color;
        colourBtn.BackColor = colorDialog1.Color;
    }

    private void clrBtn_Click(object sender, EventArgs e)
    {
        G.Clear(colorDialog2.Color);
    }

    private void button1_Click_1(object sender, EventArgs e)
    {
        colorDialog2.ShowDialog();
        panel1.BackColor = colorDialog2.Color;
        panel1Colourbtn.BackColor = colorDialog2.Color;

    }

    private void button1_Click_2(object sender, EventArgs e)
    {
        SaveFileDialog dlgSave = new SaveFileDialog();
        dlgSave.Title = "Save Image";
        dlgSave.Filter = "Bitmap Images (*.bmp)|*.bmp|All Files (*.*)|*.*";
        if (dlgSave.ShowDialog(this) == DialogResult.OK)
        {

            using (Bitmap bmp = new Bitmap(panel1.Width, panel1.Height))
            {
               // how do i save my drawing using savefiledialog? 
            }

        }
    }

Answer 1

编辑问题后我建议执行以下操作：

• 在您的表单中创建一个与面板尺寸相同的Bitmap 成员
• 从该位图创建Graphics G
• 在您的panel1_MouseMove 上绘制Graphics（有效地绘制到bitmp 中`
• 在您的panel1_Paint 在面板上绘制该位图并
• 在您的button1_Click_2 中保存该位图：

代码示例：

public partial class Form1 : Form
{
    Bitmap bmp;
    Graphics G;
    Pen myPen = new Pen(Color.Black);
    Point sp = new Point(0, 0);
    Point ep = new Point(0, 0);
    int ctrl = 0;

    public Form1()
    {
        InitializeComponent();

        // create bitmap
        bmp = new Bitmap(panel1.Width, panel1.Height);

        // create Graphics
        G = Graphics.FromImage(bmp);
        G.Clear(Color.Black);

        // redraw panel
        panel1.Invalidate();
    }

    private void panel1_Paint(object sender, PaintEventArgs e)
    {
        // draw bitmap on panel
        if (bmp != null)
            e.Grahics.DrawImage(bmp, Point.Empty);
    }

    // shortened for clarity

    private void panel1_MouseMove(object sender, MouseEventArgs e)
    {
        if(ctrl == 1)
        {
            ep = e.Location;
            // draw onto graphics -> bmp
            G.DrawLine(myPen, sp, ep);
        }
        sp = ep;

        // redraw panel
        panel1.Invalidate();
    }

    private void button1_Click_2(object sender, EventArgs e)
    {
        SaveFileDialog dlgSave = new SaveFileDialog();
        dlgSave.Title = "Save Image";
        dlgSave.Filter = "Bitmap Images (*.bmp)|*.bmp|All Files (*.*)|*.*";
        if (dlgSave.ShowDialog(this) == DialogResult.OK)
        {
             bmp.Save(dlgSave.FileName);
        }
    }
}

Answer 2

试试这个：

panel1.DrawToBitmap(bmp, new Rectangle(0, 0, panel1.Width, panel1.Height));
bmp.Save(dlgSave.FileName);