I need to increase max size (Height) in my windows Form

To clarify this question, and help you, we need to know:

1. your screen resolution.

2. why you are not focusing on re-sizing the controls to fit your available screen space by using properties such as 'Anchor and 'Dock

The observation that setting the size (and/or maximum size) property of a WinForm larger than the current screen resolution will be ignored, and the current screen size available will be used is correct. This "auto-limit" of Form size will take place both at Design-Time ... and at Run-Time, if you set the Size in code.

OriginalGriff has pointed out to you that one way to get more pixels is to change your screen resolution to a higher resolution.

But do keep in mind that you can create objects inside Forms that are larger than the maximum Form size, or screen size.

For example, my maximum screen-size right now is about 1300x788, but I can create a Panel 3000x2000, add it to a WinForm, make sure it has no Anchor or Dock property set that will bind it to the Form boundaries; I can position this giant Panel partially or fully off the screen.

And I can write code to click and drag that panel around so that the Form is functioning as a "viewport" on that Panel.

... edit #1 ... you can do the same thing with a UserControl:

UserControl1 uc1 = new UserControl1();
uc1.Dock = DockStyle.None;
uc1.Anchor = AnchorStyles.None;
uc1.MaximumSize = new Size(1500, 1200);
uc1.MinimumSize = new Size(1500, 1200);
uc1.Size = new Size(1500, 1200);
uc1.Location = new Point(-1000, -900);
this.Controls.Add(uc1);
uc1.Show();

Whether Panels or UserControls would meet your needs in this scenario: I don't know.

In any case it would be good to know more about these controls of yours that are "too big:" what are they : can they be put in some container that will let you scroll them ? And so forth.

You need to assign new value to System.Windows.Forms.Form.MaximumSize. Not Size, Width or Height.

—SA

Either just hover your mouse over the bottom of the form in the designer, and when it changes shape to a double headed arrow stretch the form to the desired height, or change the Height of the Form directly via the Property pane (it's part of Size, along with Width) You can also set the Size directly from your Form constructor if you need to.

you can change the window stte property to maximized.
after that whenever you open the form that size is maximum as your sereen or os

Hey. In the event load you can add this:

VB.net

Me.MaximumSize = New Size(0, 100) 'just to change to height maxium size
Me.MaximumSize = New Size(100, 0) 'just change the width maxium size
Me.MaximumSize = New Size(100, 100) 'change both

C#

this.MaximumSize = new Size(0, 100);
//just to change to height maxium size
this.MaximumSize = new Size(100, 0);
//just change the width maxium size
	//change both
this.MaximumSize = new Size(100, 100);

Hey, instead of using a form, use User Control.

Hey, instead of using a form which has a limited size. Use a user control

go to solution explorer >> and new item
choose User Control

Load your User Control to a panel.

Private Sub frmUpdateEmployee_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Dim usrCntl As New frmUpdateEmployeeData
Me.Panel1.Controls.Add(usrCntl)
usrCntl.Show()
Panel1.AutoScroll = True
End Sub