Search and Highlight Text in Windows Form RichTextBox using C# and VB.Net

Hi dnnyobi,

Check this example. Now please take its reference and correct your code.

Code

C#

private void Form1_Load(object sender, EventArgs e)
{
    richTextBox1.Text = "Writing about yourself can seem embarrassing at first. " +
                        "Cover letters, personal essays, and bio notes about yourself come with some " +
                        "specific tricks and tips that can make it a lot less intimidating when choosing style and content. " +
                        "Learn the basics and you will be able to make your personal writing stand out";
    txtWord.Text = "and";
}

private void btnCount_Click(object sender, EventArgs e)
{
    for (int i = 0; i < richTextBox1.TextLength; i++)
    {
        richTextBox1.Find(txtWord.Text.Trim(), i, RichTextBoxFinds.WholeWord);
        richTextBox1.SelectionColor = Color.Red;
        richTextBox1.SelectionBackColor = Color.Yellow;
    }

    int count = 0;
    for (int i = 0; i < richTextBox1.Text.Split(' ').Length; i++)
    {
        if (richTextBox1.Text.Split(' ')[i].Trim().ToLower() == txtWord.Text.Trim())
        {
            count = count + 1;
        }
    }
    lblCount.Text = count.ToString();
}

VB.Net

Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
    richTextBox1.Text = "Writing about yourself can seem embarrassing at first. " +
                        "Cover letters, personal essays, and bio notes about yourself come with some " +
                        "specific tricks and tips that can make it a lot less intimidating when choosing style and content. " +
                        "Learn the basics and you will be able to make your personal writing stand out"
    txtWord.Text = "and"
End Sub

Private Sub btnCount_Click(sender As System.Object, e As System.EventArgs) Handles btnCount.Click
    For i = 1 To richTextBox1.TextLength
        richTextBox1.Find(txtWord.Text.Trim(), i, RichTextBoxFinds.WholeWord)
        richTextBox1.SelectionColor = Color.Red
        richTextBox1.SelectionBackColor = Color.Yellow
    Next

    Dim count As Integer
    For i = 1 To richTextBox1.Text.Split(" ").Length - 1
        If richTextBox1.Text.Split(" ")(i).Trim().ToLower() = txtWord.Text.Trim() Then
            count = count + 1
        End If
    Next
    lblCount.Text = count.ToString()
End Sub

Screenshot