Form start effects

"Effect Chart"


"Train of Thought":

In the form of the onload first make the form invisible, and then from the inside out, one layer to draw rectangle, and finally let the form visible

Difficulties

The first output of the rectangle to have a place to show that the Main form is not, because when the rectangle, the form is not visible, here using the desktop desktop

"Code as follows"

1. Join namespaces

Using System.Drawing.Imaging;

Using System.Runtime.InteropServices;

2. Declaring Win32 Api GetDC ()

[DllImport ("user32")]

public static extern system.intptr GetDC (system.intptr DC);

3. Declaring variables

System.Drawing.Graphics G; Draw a tablet

Pen p=new Pen (color.black,1); Brush

int startx,starty,wx,wy,step; Startx,starty,wx,wy determines a rectangle

int cx,cy; Cx,cy the width and height of the client for form

4. Add the following code to the OnLoad on form

This. Visible=false;

Step=1;

G=GRAPHICS.FROMHDC (GetDC (System.IntPtr.Zero));

Cx=this. Clientsize.width;

Cy=this. Clientsize.height;

This. Visible=false;

Step=1;

while (STEP<=CX/2)

{

Startx=cx/2-step;

STARTY=CY*STARTX/CX;

Wx=2*step;

WY=WX*CY/CX;

Startx+=this. Left;

Starty+=this. Top+this. Height-this.clientsize.height;

G.drawrectangle (P,startx,starty,wx,wy);

System.Threading.Thread.Sleep (100);

step+=10;

}

This. Visible=true;



PS: This is the first time to publish the original, everyone a lot of advice