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How To Make an AutoSizeTextBox

saratan60

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13 Oct 2008CPOL

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How to size a TextBox to fit its contents

AutoSizeTextBoxDemo

Introduction

This small Windows application makes any TextBox fit its contents like Google toolbar's Search TextBox in Internet Explorer.

Background

This application is very easy to understand and needs no particular background.

Using the Code

We use the TextChanged event of the TextBox to resize it. First of all, we need to get the Graphics object from TextBox using the CreateGraphics() method inherited from the Control class.

Then, use the MeasureString method that has several overloads. The simplest of them gets two parameters, a String and a Font object to determine the width of a given string. The return value for this method is a SizeF structure containing Width and Height. We also use a padding value to prevent text from sticking to the right border of TextBox.

VB.NET

Private Sub TextBox1_TextChanged(ByVal sender As System.Object, 
	ByVal e As System.EventArgs) Handles TextBox1.TextChanged
    Dim g = TextBox1.CreateGraphics()
    Dim s As SizeF = g.MeasureString(TextBox1.Text, TextBox1.Font)
    TextBox1.Width = s.Width + NumericUpDownPadding.Value      
End Sub

History

13^th October, 2008: Initial post

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Written By

saratan60

Web Developer

Iran (Islamic Republic of)

This member has not yet provided a Biography. Assume it's interesting and varied, and probably something to do with programming.

Comments and Discussions

User Control - VB.Net Version

SumitSaha20-Nov-15 15:17

20-Nov-15 15:17

'The following is the vb.net version of the user control
Imports System
Imports System.ComponentModel
Imports System.Drawing
Imports System.Windows.Forms

'Namespace WindowsFormsApplication2
Public Class AutoSizeTextBox
Inherits TextBox
#region " Properties"
<Description("Minim width of the textbox")> _
<DefaultValue(80)> _
Public Property MinWidth() As Integer
Get
Return m_MinWidth
End Get
Set
m_MinWidth = Value
End Set
End Property
Private m_MinWidth As Integer

<Description("Maximum width of the textbox")> _
<DefaultValue(200)> _
Public Property MaxWidth() As Integer
Get
Return m_MaxWidth
End Get
Set
m_MaxWidth = Value
End Set
End Property
Private m_MaxWidth As Integer

<Description("Padding")> _
<DefaultValue(10)> _
Public Shadows Property Padding() As Integer
Get
Return m_Padding
End Get
Set
m_Padding = Value
End Set
End Property
Private Shadows m_Padding As Integer
#end region
'---------------------------------------------------------------------
#region " Ctor"
Public Sub New()
MyBase.New()
Me.MinWidth = 80
Me.MaxWidth = 200
Me.Padding = 10
End Sub
#end region
'---------------------------------------------------------------------
#region " Overrides"
Protected Overrides Sub OnTextChanged(e As EventArgs)
' "Inform" the base:
MyBase.OnTextChanged(e)

Using g As Graphics = Me.CreateGraphics()
Dim size As SizeF = g.MeasureString(Me.Text, Me.Font)
'Me.Width = DirectCast(size.Width, Integer) + Me.Padding
Me.Width = CInt(size.Width) + Me.Padding
g.Dispose()
End Using
End Sub
#end region
End Class

-- modified 20-Nov-15 21:25pm.

Günther M. FOIDL14-Oct-08 9:07

Günther M. FOIDL

14-Oct-08 9:07

Hi,

very nice idea.

I've taken your code and putted it into an user control. Here's the (C#)-Code:

C#

using System;
using System.ComponentModel;
using System.Drawing;
using System.Windows.Forms;

namespace WindowsFormsApplication2
{
	public class AutoSizeTextBox : TextBox
	{
		#region Properties
		[Description("Minim width of the textbox")]
		[DefaultValue(80)]
		public int MinWidth { get; set; }

		[Description("Maximum width of the textbox")]
		[DefaultValue(200)]
		public int MaxWidth { get; set; }

		[Description("Padding")]
		[DefaultValue(10)]
		public new int Padding { get; set; }
		#endregion
		//---------------------------------------------------------------------
		#region Ctor
		public AutoSizeTextBox() : base()
		{
			this.MinWidth = 80;
			this.MaxWidth = 200;
			this.Padding = 10;
		}
		#endregion
		//---------------------------------------------------------------------
		#region Overrides
		protected override void OnTextChanged(EventArgs e)
		{
			// "Inform" the base:
			base.OnTextChanged(e);

			using (Graphics g = this.CreateGraphics())
			{
				SizeF size = g.MeasureString(this.Text, this.Font);
				this.Width = (int)size.Width + this.Padding;
			}
		}
		#endregion
	}
}

Cheers
Günther

Re: UserControl

Jon_Boy21-Oct-08 1:44

21-Oct-08 1:44

saratan,

Good job on submitting your first article and for sharing your code/ideas with others.

Gunther is right, that in this instance your code would be more efficient and reusable in a user control.

Any suggestions, ideas, or 'constructive criticism' are always welcome.

JoseMenendez14-Oct-08 7:46

14-Oct-08 7:46

You're missing a line like this

g.Dispose()

after the Width assign.

Otherwise, you'll be accumulating memory on each event.

Jm

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