C# Dispose()釋放順序雜談

weixin_34304013發表於2012-02-17
C#
View Code 
public void drawWord_first(object sender, PaintEventArgs e) 
        {
            Graphics gd = e.Graphics;
//g.SmoothingMode = SmoothingMode.AntiAlias;
            GraphicsPath stringPath = new GraphicsPath();
            charInfo chars=new charInfo();
string drawWords = chars.getChars();
            stringPath.AddString(chars.getChars(), new FontFamily("楷體_GB2312"), 0, 96, new Point(0, 0), StringFormat.GenericDefault);
            gd.DrawPath(new Pen(Brushes.Blue),stringPath);
            gd.Dispose();

        }
View Code 
public void OnPaint_drawTian(object sender, PaintEventArgs e)
        {
            Graphics g = e.Graphics;
this.tianHeight = 200;
this.tianWidth = 200;
this.tianLeftTop = new Point(0,0);
this.tianRightTop = new Point(this.tianWidth,0);
this.tianLeftBottom = new Point(0,this.tianHeight);
this.tianRightBottom = new Point(this.tianWidth,this.tianHeight);
this.tianTopCenter = new Point(this.tianWidth/2,0);
this.tianBottomCenter=new Point(this.tianWidth/2,this.tianHeight);
this.tianLeftCenter = new Point(0,this.tianHeight/2);
this.tianRightCenter = new Point(this.tianWidth,this.tianHeight/2);

this.tianRectangle = new Rectangle(this.tianLeftTop,new Size(this.tianWidth,this.tianHeight));
this.tianPen=new Pen(Brushes.Red,2);
this.tianPen.DashStyle = DashStyle.DashDot;
            g.DrawLine(this.tianPen, this.tianRectangle.Left, this.tianRectangle.Top, this.tianRectangle.Left + this.tianWidth, this.tianRectangle.Bottom);
            g.DrawLine(this.tianPen,this.tianRightTop,this.tianLeftBottom);
            g.DrawLine(this.tianPen,this.tianLeftCenter,this.tianRightCenter);
            g.DrawLine(this.tianPen,this.tianTopCenter,this.tianBottomCenter);
this.tianPen.DashStyle = DashStyle.Solid;
            g.DrawRectangle(this.tianPen,this.tianRectangle);
//g.Dispose();
        }
     

這樣釋放記憶體會報 引數無效 異常，經過思索，貌似第一個g物件被釋放掉以後，第二個繪製就會成問題，所以正確寫法應當如下：

public void OnPaint_drawTian(object sender, PaintEventArgs e){...//g.Dispose();}
public void drawWord_first(object sender, PaintEventArgs e){...g.Dispose();}                
請問大家，這樣寫對不，兩個函式緊挨著被呼叫(註釋掉第一個dispose語句就是了)

另外記憶體的釋放順序應該與使用的順序相反...

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Dispose與Close沒有任何關係.它們的共同點是遵循一個相似的約定. 
Dispose的約定是,這個方法將釋放該例項所佔用的所有資源,銷燬自身. 
注意Dispose的約定是釋放所有資源並銷燬自身,就是說大多數情況下,被Dispose掉的例項都不應該被再次使用. 
如果一個類同時擁有Dispose和Close方法,一般來說,Dispose中都會呼叫Close方法.

 

 

 

Close   只是關閉而已,沒有釋放真正的釋放資源,可以重新開啟 
Dispose   是把物件銷燬,將不再存在 

 

Close是停業整頓，Dispose是炸燬；

 

Close是關門，Dispose是破產。


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