Example Application: The HTML Body Tag Formatter

	Example Application: The HTML Body Tag Formatter

Description

A scroll bar is used to navigate a bar using a thumb. While navigating, you can get the current value of the control. This application explores the properties of scroll bars.

Application: Creating the Application

Start a new Windows Application named HTMLBodyTag1

Design the form as follows:

Control	Name	Text	Other Properties
GroupBox		Body Attributes
RadioButton	rdoBackground	Background	Checked: True
TextBox	txtBackground	#000000
RadioButton	rdoText	Text
TextBox	txtText	#0000FF
RadioButton	rdoLink	Link
TextBox	txtLink	#FF0000
RadioButton	rdoActiveLink	Active Link
TextBox	txtActiveLink	#008000
RadioButton	rdoVisitedLink	Visited Link
TextBox	txtVisitedLink	#800000
Panel	pnlPreview		BackColor: White BorderStyle: Fixed3D
VScrollBar	scrRed
VScrollBar	scrGreen
VScrollBar	scrBlue
Label		R
Label		G
Label		B
Panel	pnlBody		BackColor: White BorderStyle: Fixed3D
TextBox	txtTextPreview	Body tag formatter and colorizer	BorderStyle: None ForeColor: Blue TextAlign: Center
TextBox	txtLinkPreview	Sample text as link	BorderStyle: None ForeColor: Red TextAlign: Center
TextBox	txtALinkPreview	Current active link	BorderStyle: None ForeColor: Green TextAlign: Center
TextBox	txtVLinkPreview	This link has been visited	BorderStyle: None ForeColor: Maroon TextAlign: Center
GroupBox		Color's Values
Label		Red:
TextBox	txtRed	0
Label		Green:
TextBox	txtGreen	0
Label		Blue:
TextBox	txtBlue	0
Button	btnCopy	Copy
Button	btnClose	Close
TextBox	txtResult	<body bgcolor="#FFFFFF" text="#0000FF" link="#FF0000" alink="#008000" vlink="#800000">

On the form, click one of the scroll bars
Press and hold Ctrl
Click the other two scroll bars and release Ctrl
In the Properties window, click Maximum, type 255, and press Enter
Click an unoccupied area of the form to make sure no control is selected
On the form, click one of the scroll bars
Press and hold Ctrl
Click the other two scroll bars and release Ctrl
In the Properties window, click LargeChange, type 1, and press Enter
Right-click the form and click View Code

Change the file as follows:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace HTMLBodyTag1
{
    public partial class Form1 : Form
    {
        private string HexBG, HexText, HexLink, HexALink, HexVLink;

        public Form1()
        {
            InitializeComponent();
        }

        internal void ApplyColor()
        {
            // Retrieve the current hexadecimal colors from their Edit controls
            HexBG = txtBackground.Text;
            HexText = txtText.Text;
            HexLink = txtLink.Text;
            HexALink = txtActiveLink.Text;
            HexVLink = txtVisitedLink.Text;

            // Get the integral position of each ScrollBar control
            string strRed = Convert.ToString(255 - scrRed.Value);
            string strGreen = Convert.ToString(255 - scrGreen.Value);
            string strBlue = Convert.ToString(255 - scrBlue.Value);

            // Display the position of each ScrollBar
            // in its corresponding Edit control
            txtRed.Text = strRed;
            txtGreen.Text = strGreen;
            txtBlue.Text = strBlue;

            // Change the color of the Preview panel
            // according to the values of the ScrollBar positions
            pnlPreview.BackColor = Color.FromArgb(255 - scrRed.Value,
                                                  255 - scrGreen.Value,
                                                  255 - scrBlue.Value);

            string FmtRed = (255 - scrRed.Value).ToString("X");
            if (FmtRed.Length == 1)
                FmtRed = String.Concat("0", FmtRed);

            string FmtGreen = (255 - scrGreen.Value).ToString("X");
            if (FmtGreen.Length == 1)
                FmtGreen = String.Concat("0", FmtGreen);

            string FmtBlue = (255 - scrBlue.Value).ToString("X");
            if (FmtBlue.Length == 1)
                FmtBlue = String.Concat("0", FmtBlue);

            // Get the position of each ScrollBar control
            // Create a hexadecimal color starting with #
            // And display the color in the appropriate Edit control
            if (rdoBackground.Checked == true)
            {
                string BG = "#";
                BG = String.Concat(BG, FmtRed);
                BG = String.Concat(BG, FmtGreen);
                BG = String.Concat(BG, FmtBlue);

                txtBackground.Text = BG;
                pnlBody.BackColor = pnlPreview.BackColor;
                txtTextPreview.BackColor = pnlPreview.BackColor;
                txtLinkPreview.BackColor = pnlPreview.BackColor;
                txtALinkPreview.BackColor = pnlPreview.BackColor;
                txtVLinkPreview.BackColor = pnlPreview.BackColor;

                HexBG = txtBackground.Text;
            }
            else if (rdoText.Checked == true)
            {
                string Txt = "#";
                Txt = String.Concat(Txt, FmtRed);
                Txt = String.Concat(Txt, FmtGreen);
                Txt = String.Concat(Txt, FmtBlue);

                txtText.Text = Txt;
                txtTextPreview.ForeColor = Color.FromArgb(255 - scrRed.Value,
                                                          255 - scrGreen.Value,
                                                          255 - scrBlue.Value);
                HexText = txtText.Text;
            }
            else if (rdoLink.Checked == true)
            {
                string TL = "#";
                TL = String.Concat(TL, FmtRed);
                TL = String.Concat(TL, FmtGreen);
                TL = String.Concat(TL, FmtBlue);

                txtLink.Text = TL;
                txtLinkPreview.ForeColor = Color.FromArgb(255 - scrRed.Value,
                                                          255 - scrGreen.Value,
                                                          255 - scrBlue.Value);

                HexLink = txtLink.Text;
            }
            else if (rdoActiveLink.Checked == true)
            {
                string AL = "#";
                AL = String.Concat(AL, FmtRed);
                AL = String.Concat(AL, FmtGreen);
                AL = String.Concat(AL, FmtBlue);

                txtActiveLink.Text = AL;
                txtALinkPreview.ForeColor = Color.FromArgb(255 - scrRed.Value,
                                                           255 - scrGreen.Value,
                                                           255 - scrBlue.Value);

                HexALink = txtActiveLink.Text;
            }
            else if (rdoVisitedLink.Checked == true)
            {
                string VL = "#";
                VL = String.Concat(VL, FmtRed);
                VL = String.Concat(VL, FmtGreen);
                VL = String.Concat(VL, FmtBlue);

                txtVisitedLink.Text = VL;
                txtVLinkPreview.ForeColor = Color.FromArgb(255 - scrRed.Value,
                                                           255 - scrGreen.Value,
                                                           255 - scrBlue.Value);

                HexVLink = txtVisitedLink.Text;
            }

            // Update the contents of the bottom text box
            string BD = "<body bgcolor=\"";
            BD = String.Concat(BD, HexBG);
            BD = String.Concat(BD, "\" text=\"");
            BD = String.Concat(BD, HexText);
            BD = String.Concat(BD, "\" link=\"");
            BD = String.Concat(BD, HexLink);
            BD = String.Concat(BD, "\" alink=\"");
            BD = String.Concat(BD, HexALink);
            BD = String.Concat(BD, "\" vlink=\"");
            BD = String.Concat(BD, HexVLink);
            BD = String.Concat(BD, "\">");

            txtResult.Text = BD;
        }
    }
}

Return to the form and double-click the left scroll bar

Implement its event as follows:

private void scrRed_Scroll(object sender, ScrollEventArgs e)
{
    ApplyColor();
}

Return to the form and double-click the middle scroll bar

Implement its event as follows:

private void scrGreen_Scroll(object sender, ScrollEventArgs e)
{
          ApplyColor();
}

Return to the form and double-click the right scroll bar

Implement its event as follows:

private void scrBlue_Scroll(object sender, ScrollEventArgs e)
{
         ApplyColor();
}

Execute the application to test the form
Close the form and return to your programming environment

When the user clicks a radio button from the Body Attributes group box, we need to display its color on the Preview panel. When a particular button is clicked, we will retrieve the color of its font from the Body text box, translate that color into red, green, and blue values, and then use those values to automatically update the scroll bars and the edit boxes. While we are at it, we also need to update the corresponding text box in the Body Attributes group box. Since this functionality will be used by all radio buttons in the group, we will use a global function to which we can pass two variables.
When the user clicks a particular radio button, that button is represented by a text box in the lower-left Body section. We need to get the color of that edit box and pass it to our function. Since the clicked radio button has a corresponding text box in the Body Attributes group box, we need to change/update that value with the hexadecimal value of the first argument. Therefore, we will pass a string argument to our function.
In the Code Editor, just after the closing curly bracket of the scrBlue_Scroll event, create the following method:

internal void ClickOption(System.Drawing.Color Clr, String Result)
{
	// These variables will hold the red, green, and blue
	// values of the passed color
	int red, green, blue;

	// Colorize the Preview panel with the passed color
	pnlPreview.BackColor = Clr;

	// Get the red value of the color of the Preview panel
	red = 255 - pnlPreview.BackColor.R;
	// Get the green value of the color of the Preview panel
	green = 255 - pnlPreview.BackColor.G;
	// Get the blue value of the color of the Preview panel
	blue = 255 - pnlPreview.BackColor.B;

	// Now that we have the red, green, and blue values of the color,
	// Update the scroll bars with the new values
	scrRed.Value   = red;
	scrGreen.Value = green;
	scrBlue.Value  = blue;

	// Update the red, green, and blue values
	// of the Numeric Values group box
	txtRed.Text   = red.ToString();
	txtGreen.Text = green.ToString();
	txtBlue.Text  = blue.ToString();

	// Update the string that was passed using
	// the retrieved red, green, and blue values
	Result = String.Concat(Result, "#");
	Result = String.Concat(Result, red.ToString("X"));
	Result = String.Concat(Result, green.ToString("X"));
	Result = String.Concat(Result, blue.ToString("X"));
}

Return to the form

Double-click the Background radio button and implement its event as follows:

private void rdoBackground_CheckedChanged(object sender, EventArgs e)
{
            // If the user clicks Background radio button
            // set color of the panel to that of the radio button
            Color BGColor = pnlBody.BackColor;

            pnlBody.BackColor = BGColor;

            // Call the ClickOption() method to calculate
            // the hexadecimal value of the color
            ClickOption(pnlBody.BackColor, txtBackground.Text);
            HexBG = txtBackground.Text;
}

Return to the form

Double-click the Text radio button and implement its event as follows:

private void rdoText_CheckedChanged(object sender, EventArgs e)
{
            Color BGColor = pnlBody.BackColor;
            txtTextPreview.BackColor = BGColor;

            ClickOption(txtTextPreview.ForeColor, txtText.Text);
            HexText = txtText.Text;   
}

Return to the form

Double-click the Link radio button and implement its event as follows:

private void rdoLink_CheckedChanged(object sender, EventArgs e)
{
            Color BGColor = pnlBody.BackColor;
            txtLinkPreview.BackColor = BGColor;

            ClickOption(txtLinkPreview.ForeColor, txtLink.Text);
            HexLink = txtLink.Text; 
}

Return to the form

Double-click the Active Link radio button and implement its event as follows:

private void rdoActiveLink_CheckedChanged(object sender, EventArgs e)
{
            Color BGColor = pnlBody.BackColor;
            txtALinkPreview.BackColor = BGColor;

            ClickOption(txtALinkPreview.ForeColor, txtActiveLink.Text);
            HexALink = txtActiveLink.Text;
}

Return to the form

Double-click the Visited Link radio button and implement its event as follows:

private void rdoVisitedLink_CheckedChanged(object sender, EventArgs e)
{
            Color BGColor = pnlBody.BackColor;
            txtVLinkPreview.BackColor = BGColor;

            ClickOption(txtVLinkPreview.ForeColor, txtVisitedLink.Text);
            HexVLink = txtVisitedLink.Text;  
}

Return to the form

Double-click the Copy button and implement it as follows:

private void btnCopy_Click(object sender, EventArgs e)
{
            txtResult.SelectAll();
            txtResult.Copy();
}

Return to the form

Double-click the Close button and implement it as follows:

private void btnClose_Click(object sender, EventArgs e)
{
            Close();
}

Execute the application
Close the form


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