How can I get the rectangle of the text in a Textbox?

Original - C# Code /// <summary> /// Use this method only once, per textbox. Created event-handler will keep /// track of text changes, and autosize textbox automaticaly. /// The +6 makes a margin of error. You can customize the number if needed. /// </summary> public static void KeepAutoresizingThis(TextBox textbox) { Graphics graphics = textbox.CreateGraphics(); Size originalSize = textbox.Size; textbox.TextChanged += new EventHandler(delegate { int suggestedWidth = (int)graphics.MeasureString(textbox.Text, textbox.Font).Width + 6; if (suggestedWidth < originalSize.Width) textbox.Size = originalSize; else textbox.Width = suggestedWidth; }); }

 
/// <summary>
/// Use this method only once, per textbox. Created event-handler will keep 
/// track of text changes, and autosize textbox automaticaly. 
/// The +6 makes a margin of error. You can customize the number if needed. 
/// </summary>
public static void KeepAutoresizingThis(TextBox textbox)
{
    Graphics graphics = textbox.CreateGraphics();
    Size originalSize = textbox.Size;
 
    textbox.TextChanged += new EventHandler(delegate
        {
            int suggestedWidth =
                (int)graphics.MeasureString(textbox.Text, textbox.Font).Width
                + 6;
 
            if (suggestedWidth < originalSize.Width)
                textbox.Size = originalSize;
            else
                textbox.Width = suggestedWidth;
        });
} 

        Size GetTextSize(TextBox tb)
        {
            // initialize some variables
            Graphics g = tb.CreateGraphics();
            SizeF size = g.MeasureString(tb.Text, tb.Font, tb.Width - 6); // the -6 should account for the diff between the textbox.clientrectangle.width and the textbox.width
            int bottomPadding = 20;
            int desiredHeight = (int)size.Height + 7 + bottomPadding; // the +7 should account for the diff between the textbox.clientrectangle.height and textbox.height
            int heightOfSingleLineOfText = tb.Font.Height;

            // if there are any characters at all...
            if (tb.TextLength > 0)
            {
                // and if the last char is a newline...
                if (tb.Text[tb.TextLength - 1] == '\n')
                {
                    // add an extra line
                    desiredHeight += heightOfSingleLineOfText;
                }
            }

            // cycle through the characters
            for (int i = 0; i < tb.TextLength; i++)
            {
                // if the char is a newline
                // and is preceded by a newline...
                if (tb.Text[i] == '\n' && tb.Text[i - 1] == '\n')
                {
                    // add an extra "line"
                    desiredHeight += heightOfSingleLineOfText;
                }
            }

            size.Height = desiredHeight;
            return new Size((int)size.Width, (int)size.Height);
        }

// the form was designed in the designer so the 
// textbox1 object was created in the designer and
// it's code is not shown here
public partial class Form1 : Form
    {
        RichTextBox rtb = new RichTextBox();

        public Form1()
        {
            InitializeComponent();
            rtb.Size = textBox1.Size;            
            textBox1.TextChanged += new EventHandler(textBox1_TextChanged);
            rtb.ContentsResized += new ContentsResizedEventHandler(rtb_ContentsResized);
        }

        void rtb_ContentsResized(object sender, ContentsResizedEventArgs e)
        {
            textBox1.Height = e.NewRectangle.Height + 7; // +7 accounts for some diff between the textbox's clientsize and actual size.
        }


        private void textBox1_TextChanged(object sender, EventArgs e)
        {
            rtb.Text = this.textBox1.Text;
        }

public partial class Form1 : Form
    {
        RichTextBox rtb = new RichTextBox();

        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            rtb.Parent = this;  /// needed to add this!
            rtb.Visible = false;  /// needed as well!
            rtb.Size = textBox1.Size;
            rtb.ScrollBars = RichTextBoxScrollBars.None; /// also this is important!

            textBox1.TextChanged += new EventHandler(textBox1_TextChanged);
            rtb.ContentsResized += new ContentsResizedEventHandler(rtb_ContentsResized);
        }

        void rtb_ContentsResized(object sender, ContentsResizedEventArgs e)
        {
            textBox1.Height = e.NewRectangle.Height + 7;
        }

        void textBox1_TextChanged(object sender, EventArgs e)
        {
            rtb.Text = textBox1.Text;
        }
    }

    public partial class AutoSizingTextBox : UserControl
    {
        RichTextBox rtb = new RichTextBox();
        TextBox tb = new TextBox();

        [Browsable(true)]
        public new int Height
        {
            get { return this.tb.Height; }
            set { this.tb.Height = value; }
        }

        [Browsable(true)]
        public new int Width
        {
            get { return this.tb.Width; }
            set { this.tb.Width = value; }
        }

        public AutoSizingTextBox()
        {
            InitializeComponent();
            this.Size = this.tb.Size;

            this.rtb.Location = new Point(0, 0);
            this.rtb.ScrollBars = RichTextBoxScrollBars.None;
            this.rtb.Size = tb.Size;
            this.rtb.ContentsResized += new ContentsResizedEventHandler(rtb_ContentsResized);
            this.Controls.Add(rtb);

            this.tb.Size = this.Size;
            this.tb.Anchor = AnchorStyles.Left | AnchorStyles.Top | AnchorStyles.Right | AnchorStyles.Bottom;
            this.tb.Location = new Point(0, 0);
            this.tb.Multiline = true;
            this.tb.TextChanged += new EventHandler(tb_TextChanged);
            this.tb.SizeChanged += new EventHandler(tb_SizeChanged);
            this.Controls.Add(tb);
            this.tb.BringToFront();
        }       

        void tb_SizeChanged(object sender, EventArgs e)
        {
            if (this.rtb.Width != this.tb.Width)
            {
                this.rtb.Width = this.tb.Width;
                this.rtb.Height = this.tb.Height - 8;
            }

            this.Size = this.tb.Size;
        }

        void tb_TextChanged(object sender, EventArgs e)
        {
            this.rtb.Text = this.tb.Text;
        }

        void rtb_ContentsResized(object sender, ContentsResizedEventArgs e)
        {
            this.rtb.Height = e.NewRectangle.Height;            
            this.tb.Height = this.rtb.Height + 8;
        }
    }

Original - C# Code public class AutoSizingTextBox : TextBox { RichTextBox rtb = new RichTextBox(); public AutoSizingTextBox() { this.Multiline = true; this.TextChanged += new EventHandler(AutoSizingTextBox_TextChanged); this.SizeChanged += new EventHandler(AutoSizingTextBox_SizeChanged); //this.FindForm().Controls.Add(this); rtb.Location = new Point(0, 0); rtb.Parent = this.Parent; rtb.Visible = false; rtb.ScrollBars = RichTextBoxScrollBars.None; rtb.Size = this.Size; rtb.ContentsResized += new ContentsResizedEventHandler(rtb_ContentsResized); //this.FindForm().Controls.Add(rtb); } void AutoSizingTextBox_SizeChanged(object sender, EventArgs e) { rtb.Size = this.Size; } void AutoSizingTextBox_TextChanged(object sender, EventArgs e) { rtb.Text = this.Text; } void rtb_ContentsResized(object sender, ContentsResizedEventArgs e) { rtb.Height = e.NewRectangle.Height; this.Height = e.NewRectangle.Height + 8; } }

 
public class AutoSizingTextBox : TextBox
    {
        RichTextBox rtb = new RichTextBox();
 
        public AutoSizingTextBox()
        {
            this.Multiline = true;
            this.TextChanged += new EventHandler(AutoSizingTextBox_TextChanged);
            this.SizeChanged += new EventHandler(AutoSizingTextBox_SizeChanged);
            //this.FindForm().Controls.Add(this);
 
            rtb.Location = new Point(0, 0);
            rtb.Parent = this.Parent;
            rtb.Visible = false;
            rtb.ScrollBars = RichTextBoxScrollBars.None;
            rtb.Size = this.Size;
            rtb.ContentsResized += new ContentsResizedEventHandler(rtb_ContentsResized);
            //this.FindForm().Controls.Add(rtb);
        }
 
        void AutoSizingTextBox_SizeChanged(object sender, EventArgs e)
        {
            rtb.Size = this.Size;
        }
 
        void AutoSizingTextBox_TextChanged(object sender, EventArgs e)
        {
            rtb.Text = this.Text;
        }
 
        void rtb_ContentsResized(object sender, ContentsResizedEventArgs e)
        {
            rtb.Height = e.NewRectangle.Height;
            this.Height = e.NewRectangle.Height + 8;
        }
    } 

Original - c# Code using System; using System.Collections.Generic; using System.Text; using System.Windows.Forms; using System.Drawing; using System.ComponentModel; using System.Runtime.InteropServices; namespace AutoSizeableTextBox { public class AutosizeableTextbox : TextBox { // link to the SendMessage function in the user32.dll [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = false)] static extern IntPtr SendMessage(IntPtr hWnd, Int32 Msg, IntPtr wParam, IntPtr lParam); // set up some variables const int TEXTBOX_PADDING = 7; int minWidth = 10; // during instantiation, this is set to the width of a double-u int minHeight = 20; AutoSizeMode autosizeMode = AutoSizeMode.GrowOnly; bool autosize = true; // set up some useful properties public int MinimumWidth { get { return this.minWidth; } } public int MinimumHeight { get { return this.minHeight; } } [Browsable(true), Category("Autosize Properties")] public AutoSizeMode AutoSizeMode2 // see note by AutoSize2 { get { return autosizeMode; } set { autosizeMode = value; ResizeMe(); } } [Browsable(true), Category("Autosize Properties")] public bool AutoSize2 // when i called it AutoSize, whether i used "new" or "override," it would always reset itself to false at runtime. { get { return autosize; } set { autosize = value; ResizeMe(); } } // constructor public AutosizeableTextbox() { this.minWidth = TextRenderer.MeasureText("W", this.Font).Width; this.minHeight = (int)(this.FontHeight + TEXTBOX_PADDING); //this.MinimumSize = new Size(this.MinimumSize.Width, minHeight); this.FontChanged += new EventHandler(AutosizeableTextbox_FontChanged); this.TextChanged += new EventHandler(AutosizingTextbox_TextChanged); this.SizeChanged += new EventHandler(AutosizeableTextbox_SizeChanged); } void AutosizeableTextbox_FontChanged(object sender, EventArgs e) { this.minWidth = TextRenderer.MeasureText("W", this.Font).Width; this.minHeight = (int)(this.FontHeight + TEXTBOX_PADDING); ResizeMe(); } // public methods public void ForceResize() { ResizeMe(); } public void ForceResize(int minWidth, int minHeight, int width, int height) { this.MinimumSize = new Size(minWidth, minHeight); this.Size = new Size(width, height); ResizeMe(); } // event handlers void AutosizeableTextbox_SizeChanged(object sender, EventArgs e) { ResizeMe(); } void AutosizingTextbox_TextChanged(object sender, EventArgs e) { ResizeMe(); } // resize method void ResizeMe() { if (this.MinimumSize.Height < this.minHeight) this.MinimumSize = new Size(this.MinimumSize.Width, this.minHeight); if (this.MinimumSize.Width < this.minWidth) this.MinimumSize = new Size(this.minWidth, this.MinimumSize.Height); if (autosize) { if (this.Multiline) ResizeWithMultilineOn(); else ResizeWithMultilineOff(); } } // resize when multiline is true void ResizeWithMultilineOn() { double lineHeight = this.FontHeight; int lineCount = this.GetLineCount(); int newHeight = (int)(lineCount * lineHeight) + TEXTBOX_PADDING; if (newHeight < this.Height) { if (autosizeMode == AutoSizeMode.GrowAndShrink) this.Height = newHeight; } else { this.Height = newHeight; } } // resize when multiline is false void ResizeWithMultilineOff() { if (this.TextLength > 0) { int newWidth = TextRenderer.MeasureText(this.Text, this.Font).Width + this.minWidth; if (newWidth < this.Width) { if (autosizeMode == AutoSizeMode.GrowAndShrink) { this.Width = newWidth; } } else { this.Width = newWidth; } } else { if (autosizeMode == AutoSizeMode.GrowAndShrink) { this.Width = this.minWidth; // width of a double-u } } } // gets the number of lines in the textbox int GetLineCount() { const Int32 EM_GETLINECOUNT = 186; return (int)SendMessage(this.Handle, EM_GETLINECOUNT, IntPtr.Zero, IntPtr.Zero); } } }

 
using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Forms;
using System.Drawing;
using System.ComponentModel;
using System.Runtime.InteropServices;
 
 
namespace AutoSizeableTextBox
{
    public class AutosizeableTextbox : TextBox
    {
        // link to the SendMessage function in the user32.dll
        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = false)]
        static extern IntPtr SendMessage(IntPtr hWnd, Int32 Msg, IntPtr wParam, IntPtr lParam);
 
        // set up some variables
        const int TEXTBOX_PADDING = 7;
        int minWidth = 10;  // during instantiation, this is set to the width of a double-u
        int minHeight = 20;
        AutoSizeMode autosizeMode = AutoSizeMode.GrowOnly;
        bool autosize = true;
 
        // set up some useful properties
        public int MinimumWidth
        { get { return this.minWidth; } }
 
        public int MinimumHeight
        { get { return this.minHeight; } }
 
        [Browsable(true), Category("Autosize Properties")]
        public AutoSizeMode AutoSizeMode2 // see note by AutoSize2
        {
            get { return autosizeMode; }
            set
            {
                autosizeMode = value;
                ResizeMe();
            }
        }
 
        [Browsable(true), Category("Autosize Properties")]
        public bool AutoSize2 // when i called it AutoSize, whether i used "new" or "override," it would always reset itself to false at runtime.
        {
            get { return autosize; }
            set
            {
                autosize = value;
                ResizeMe();
            }
        }
 
 
        // constructor
        public AutosizeableTextbox()
        {
            this.minWidth = TextRenderer.MeasureText("W", this.Font).Width;
            this.minHeight = (int)(this.FontHeight + TEXTBOX_PADDING);
            //this.MinimumSize = new Size(this.MinimumSize.Width, minHeight);
            this.FontChanged += new EventHandler(AutosizeableTextbox_FontChanged);
            this.TextChanged += new EventHandler(AutosizingTextbox_TextChanged);
            this.SizeChanged += new EventHandler(AutosizeableTextbox_SizeChanged);
            
        }
 
        void AutosizeableTextbox_FontChanged(object sender, EventArgs e)
        {
            this.minWidth = TextRenderer.MeasureText("W", this.Font).Width;
            this.minHeight = (int)(this.FontHeight + TEXTBOX_PADDING);
            ResizeMe();
        }
 
        // public methods
        public void ForceResize()
        {
            ResizeMe();
        }
 
        public void ForceResize(int minWidth, int minHeight, int width, int height)
        {
            this.MinimumSize = new Size(minWidth, minHeight);
            this.Size = new Size(width, height);
            ResizeMe();
        }
 
        // event handlers
        void AutosizeableTextbox_SizeChanged(object sender, EventArgs e)
        {
            ResizeMe();
        }
 
        void AutosizingTextbox_TextChanged(object sender, EventArgs e)
        {
            ResizeMe();
        }
 
        // resize method
        void ResizeMe()
        {
            if (this.MinimumSize.Height < this.minHeight)
                this.MinimumSize = new Size(this.MinimumSize.Width, this.minHeight);
 
            if (this.MinimumSize.Width < this.minWidth)
                this.MinimumSize = new Size(this.minWidth, this.MinimumSize.Height);
 
            if (autosize)
            {
                if (this.Multiline)
                    ResizeWithMultilineOn();
                else
                    ResizeWithMultilineOff();
            }
        }
 
        // resize when multiline is true
        void ResizeWithMultilineOn()
        {
            double lineHeight = this.FontHeight;
            int lineCount = this.GetLineCount();
            int newHeight = (int)(lineCount * lineHeight) + TEXTBOX_PADDING;
 
            if (newHeight < this.Height)
            {
                if (autosizeMode == AutoSizeMode.GrowAndShrink)
                    this.Height = newHeight;
            }
            else
            {
                this.Height = newHeight;
            }
        }
 
        // resize when multiline is false
        void ResizeWithMultilineOff()
        {
            if (this.TextLength > 0)
            {
                int newWidth = TextRenderer.MeasureText(this.Text, this.Font).Width + this.minWidth;
                if (newWidth < this.Width)
                {
                    if (autosizeMode == AutoSizeMode.GrowAndShrink)
                    {
                        this.Width = newWidth;
                    }
                }
                else
                {
                    this.Width = newWidth;
                }
            }
            else
            {
                if (autosizeMode == AutoSizeMode.GrowAndShrink)
                {
                    this.Width = this.minWidth; // width of a double-u
                }
            }
        }
 
        // gets the number of lines in the textbox
        int GetLineCount()
        {
            const Int32 EM_GETLINECOUNT = 186;
            return (int)SendMessage(this.Handle, EM_GETLINECOUNT, IntPtr.Zero, IntPtr.Zero);
        }
    }
}