c#画图问题求救

Question

用Metafile类记录绘图过程，并保存，在刷新时可重绘

Answer 1

代码片断
foreach(DataRowView drv in childNodes)
{ 
string iFilter1="关系结点1='"+drv["任务模板id"].ToString()+"'";DataView conditionsOfThisNode=new DataView(this.dataSet1_1.task_condition_t,iFilter1,"关系结点1",DataViewRowState.CurrentRows);
foreach(DataRowView drv2 in conditionsOfThisNode)
{ 
Guid gid_1=(Guid)drv2["关系结点1"];
Guid gid_2=(Guid)drv2["关系结点2"];
drawLine(gh,gid_1,gid_2);}
}
}
private void drawLine(Graphics gh,Guid g1,Guid g2)
{ 
Point pt1=new Point();
Point pt2=new Point();
foreach(Control ctrl in this.groupBox1.Controls)
{
if((Guid)ctrl.Tag==g1)
{ 
pt1.X=ctrl.Location.X+ctrl.Width/2;
pt1.Y=ctrl.Location.Y+ctrl.Height/2;}
if((Guid)ctrl.Tag==g2)
{ pt2.X=ctrl.Location.X+ctrl.Width/2;
pt2.Y=ctrl.Location.Y+ctrl.Height/2;}
}
Pen myPen=new Pen(Color.Red);
gh.DrawLine(myPen,pt1,pt2); } 本人新手，请详细说明。

Answer 2

Drawing the line in Paint event of GroupBox.Hope it could be help.

Answer 3

原作:TheAresusing System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;namespace WindowsApplication1
{
/// <summary>
/// Form1 的摘要说明。
/// </summary>
public class Form1 : System.Windows.Forms.Form
{
private System.Windows.Forms.Label label1;
private System.Windows.Forms.Label label2;
/// <summary>
/// 必需的设计器变量。
/// </summary>
private System.ComponentModel.Container components = null; private Point mousePos; // 记录鼠标位置
private bool beginmove = false; // 记录是否可以移动  public Form1()
{
//
// Windows 窗体设计器支持所必需的
//
InitializeComponent(); //
// TODO: 在 InitializeComponent 调用后添加任何构造函数代码
//
} /// <summary>
/// 清理所有正在使用的资源。
/// </summary>
protected override void Dispose( bool disposing )
{
if( disposing )
{
if(components != null)
{
components.Dispose();
}
}
base.Dispose( disposing );
} #region Windows Form Designer generated code
/// <summary>
/// 设计器支持所需的方法 - 不要使用代码编辑器修改
/// 此方法的内容。
/// </summary>
private void InitializeComponent()
{
this.label1 = new System.Windows.Forms.Label();
this.label2 = new System.Windows.Forms.Label();
this.SuspendLayout();
// 
// label1
// 
this.label1.BackColor = System.Drawing.SystemColors.ActiveCaption;
this.label1.Location = new System.Drawing.Point(16, 48);
this.label1.Name = "label1";
this.label1.Size = new System.Drawing.Size(120, 168);
this.label1.TabIndex = 0;
this.label1.Text = "label1";
// 
// label2
// 
this.label2.BackColor = System.Drawing.SystemColors.Desktop;
this.label2.Location = new System.Drawing.Point(232, 32);
this.label2.Name = "label2";
this.label2.Size = new System.Drawing.Size(136, 192);
this.label2.TabIndex = 1;
this.label2.Text = "label2";
this.label2.MouseUp += new System.Windows.Forms.MouseEventHandler(this.label2_MouseUp);
this.label2.MouseMove += new System.Windows.Forms.MouseEventHandler(this.label2_MouseMove);
this.label2.MouseDown += new System.Windows.Forms.MouseEventHandler(this.label2_MouseDown);
// 
// Form1
// 
this.AutoScaleBaseSize = new System.Drawing.Size(6, 14);
this.ClientSize = new System.Drawing.Size(520, 286);
this.Controls.AddRange(new System.Windows.Forms.Control[] {
  this.label2,
  this.label1});
this.Name = "Form1";
this.Text = "Form1";
this.MouseDown += new System.Windows.Forms.MouseEventHandler(this.Form1_MouseDown);
this.MouseUp += new System.Windows.Forms.MouseEventHandler(this.Form1_MouseUp);
this.MouseMove += new System.Windows.Forms.MouseEventHandler(this.Form1_MouseMove);
this.ResumeLayout(false); }
#endregion public static void Main()
{
Application.Run(new Form1());
} private void drawLine(PaintEventArgs pe,Point pt1,Point pt2)
{
Graphics g = pe.Graphics;
//g.ResetClip();
Pen p = new Pen(Color.Blue,1);
g.DrawLine(p,pt1,pt2); } protected override void OnPaint(PaintEventArgs pe)
{


this.drawLine(pe,this.label1.Location + this.label1.Size ,this.label2.Location);
base.OnPaint(pe);


} private void Form1_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
{

} private void Form1_MouseMove(object sender, System.Windows.Forms.MouseEventArgs e)
{ } private void Form1_MouseUp(object sender, System.Windows.Forms.MouseEventArgs e)
{

} private void label2_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
{
beginmove = true;//开始移动
mousePos = new Point(e.X, e.Y); 
} private void label2_MouseMove(object sender, System.Windows.Forms.MouseEventArgs e)
{
if(beginmove)
{
int diffx,diffy;
diffx = mousePos.X - e.X;
diffy = mousePos.Y - e.Y;
this.label2.Location = new Point(label2.Location.X-diffx,label2.Location.Y-diffy);
} 
Invalidate();
// System.Windows.Forms.PaintEventArgs ex=null;
// this.InvokePaint(this.label2,ex);
} private void label2_MouseUp(object sender, System.Windows.Forms.MouseEventArgs e)
{
beginmove = false;//停止移动 

} }
}