Background
I was searching for a way to snap a form to the borders of the screen, like what WinAmp does, and found one here. But my form was without border (FormBorderStyle = None), and the code I found here didn't work great for forms without border. It also seemed like a little complicated for beginners (almost like me!), so I tried to write it myself, and wrote a more simple and easy to understand code. This is also a very simple way to move forms without border.
Code
The following variables should be declared right after Public Class ... so that other procedures can access them.
Dim X1 As Integer, Y1 As Integer, WR As Rectangle
Now put the following code in the MouseDown event of the form:
Private Sub Form1_MouseDown(ByVal sender As Object, _
ByVal e As System.Windows.Forms.MouseEventArgs) _
Handles Me.MouseDown
X1 = e.X
Y1 = e.Y
WR = Screen.GetWorkingArea(Me)
End Sub
This piece of code records the point where the mouse was clicked and also the working area of the desktop. Now the main part of the code should be put in the MouseMove event of the form.
Private Sub Form1_MouseMove(ByVal sender As Object, _
ByVal e As System.Windows.Forms.MouseEventArgs) _
Handles Me.MouseMove
If Not e.Button = Windows.Forms.MouseButtons.Left Then Exit Sub
Dim NewX As Integer = Me.Left + (e.X - X1)
Dim NewY As Integer = Me.Top + (e.Y - Y1)
Dim W As Integer = Me.Width
Dim H As Integer = Me.Height
If NewY >= WR.Top - 15 And NewY <= WR.Top + 15 Then
Me.Top = WR.Top
ElseIf NewY + H > WR.Bottom - 15 And NewY + H < WR.Bottom + 15 Then
Me.Top = WR.Bottom - H
Else
Me.Top = NewY
End If
If NewX >= WR.Left - 15 And NewX <= WR.Left + 15 Then
Me.Left = WR.Left
ElseIf NewX + W > WR.Right - 15 And NewX + W < WR.Right + 15 Then
Me.Left = WR.Right - W
Else
Me.Left = NewX
End If
End Sub
This code calculates the new position of the form when you move the mouse with left button pressed down, and snaps it when it gets near the borders of the screen. The default distance is 15, but you can change it, or replace it with a variable to change it dynamically during runtime.
Significance
It is a very easy to understand code and has no complications. It also uses a very simple method to move a form which has no border.
