Highlights Text in a Text File in C#

Submitted by donbermoy on Tuesday, November 3, 2015 - 20:10.
In this tutorial, I will teach you how to create a program load a text file in the richtextbox, search a particular word, and then highlights it. So, now let's start this tutorial! 1. Let's start with creating a Windows Form Application for this tutorial by following the following steps in Microsoft Visual Studio 2010: Go to File, click New Project, and choose Windows Application. 2. Add two buttons; the open text file button and the search button, one textbox for the user to type and search a particular word, and a richtextbox to display the contents of the text file. design 3. Now, have this code below. Import first the namespace of IO to access the streamreaders for opening a text file.
  1. using System.IO;
Now in button1, we will have an openfiledialog that will trigger to open a text file. And after choosing a text file, it will load in the richtextbox.
  1.         private void button1_Click(object sender, EventArgs e)
  2.         {
  3.          
  4.             OpenFileDialog ofd = new OpenFileDialog();
  5.  
  6.             if (ofd.ShowDialog() == DialogResult.OK)
  7.             {
  8.                 //get the filename of the text file
  9.                 string filename = ofd.FileName;
  10.                 //read all the contents
  11.                 string textfile = File.ReadAllText(filename);
  12.                 // display the contents in the richtextbox
  13.                 rtDisplay.Text = textfile;
  14.             }
  15.  
  16.         }
Lastly, this code is for button2 that will trigger to highlights the searched word in the textbox.
  1.         private void button2_Click(object sender, EventArgs e)
  2.         {
  3.             //string words = txtSearch.Text;
  4.             //rtDisplay.Text = "";
  5.             //rtDisplay.Text = words;
  6.             int index = 0;
  7.  
  8.             // if the textbox has an inputted text
  9.             while (index < rtDisplay.Text.LastIndexOf(txtSearch.Text)){
  10.                 //find text in the searched word
  11.                 rtDisplay.Find(txtSearch.Text,rtDisplay.TextLength, RichTextBoxFinds.None);
  12.                 // highlights the word with a color yellow
  13.                 rtDisplay.SelectionBackColor = Color.Yellow;
  14.  
  15.                 // highlights all those words that is the same with the searched word in the textbox
  16.                 index = rtDisplay.Text.IndexOf(txtSearch.Text, index) + 1;
  17.             }
  18.  
  19.         }
Output: output For more inquiries and need programmer for your thesis systems in any kind of programming languages, just contact my number below. Best Regards, Engr. Lyndon Bermoy IT Instructor/System Developer/Android Developer/Freelance Programmer If you have some queries, feel free to contact the number or e-mail below. Mobile: 09488225971 Landline: 826-9296 E-mail:[email protected] Add and Follow me on Facebook: https://www.facebook.com/donzzsky Visit and like my page on Facebook at: https://www.facebook.com/BermzISware
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Highlights Text in a Text File in C#
highlight text
text file
search words
c#

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