C# RichTextBox Select specified Text

Question

I have a RichTextBox with -by example- this text:

"This is my Text"

Now I want to "search" the RichTextBox for a Text (String), by example:

"Text"

Now "Text" should be selected/highlighted (for each one) in the RichTextBox..

There is something like:

myRichTextBox.Select();

but here I have to set a StartPosition and so on, but I want to search for String!

How could I do this? (Searched stackoverflow, didn't find something similiar..)

Solution 1

     int start = 0;
int indexOfSearchText = 0;
private void btnFind_Click(object sender, EventArgs e)
        {
            int startindex = 0;

            if(txtSearch.Text.Length > 0)
                startindex = FindMyText(txtSearch.Text.Trim(), start, rtb.Text.Length);

            // If string was found in the RichTextBox, highlight it
            if (startindex >= 0)
            {
                // Set the highlight color as red
                rtb.SelectionColor = Color.Red;
                // Find the end index. End Index = number of characters in textbox
                int endindex = txtSearch.Text.Length;
                // Highlight the search string
                rtb.Select(startindex, endindex);
                // mark the start position after the position of
                // last search string
                start = startindex + endindex;
            }
        }




public int FindMyText(string txtToSearch, int searchStart, int searchEnd)
        {
            // Unselect the previously searched string
            if (searchStart > 0 && searchEnd > 0 && indexOfSearchText >= 0)
            {
                rtb.Undo();
            }

            // Set the return value to -1 by default.
            int retVal = -1;

            // A valid starting index should be specified.
            // if indexOfSearchText = -1, the end of search
            if (searchStart >= 0 && indexOfSearchText >=0)
            {
                // A valid ending index
                if (searchEnd > searchStart || searchEnd == -1)
                {
                    // Find the position of search string in RichTextBox
                    indexOfSearchText = rtb.Find(txtToSearch, searchStart, searchEnd, RichTextBoxFinds.None);
                    // Determine whether the text was found in richTextBox1.
                    if (indexOfSearchText != -1)
                    {
                        // Return the index to the specified search text.
                        retVal = indexOfSearchText;
                    }
                }
            }
            return retVal;
        }



private void textBox1_TextChanged(object sender, EventArgs e)
        {
            start = 0;
            indexOfSearchText = 0;
        }

CheckOut this article if you dont understand this code... http://www.dotnetcurry.com/ShowArticle.aspx?ID=146

Solution 2

You can only have one selection in a text box. What you want is to highlight the found text.
You could achieve it like this:

1. Find the positions of the text you want to highlight using repeated calls to myRichTextBox.Text.IndexOf with the last found index + 1 as the start position.
2. Highlight the found texts using the default RichTextBox capabilities.

Solution 3

You can use the Find method to find the startindex of your searched text:

int indexToText = myRichTextBox.Find(searchText);

You can then use this index and the Select method to select the text:

int endIndex = searchText.Length;
myRichTextBox.Select(indexToText , endIndex);

Comments

[eMi]

Yes, I want to highlight the found text.. Thank you 4 showing me, How I could achieve this.. but how does it looks like in code? (I'm quite new in C#)

[eMi]

thx for your answer, this is also a possible way yeah, but how I meant to highlight, with select I cant select more than 1 Word in the rtb

[eMi]

yes, it works only 4 one word.. But I want all words selected with ONE Button-Click.. thats the problem..

[sikender]

you can implement it as whole word selected, it is helping code to you understand that how search function will work in rich text box.

[eMi]

I knew before, how do I mark text in the richtextbox, but not how to mark more than one text at once

[eMi]

ok I did it, I used a Timer.. Now I can select all this words calling the method from this code eact 100ms..

[sikender]

Good. Keep in mind that, if you find any code snippet. It's not always that it's a copy-paste and your work is done. sometime you have to need patch work into that as make that code run like wise your functionality. Thanks. and good attempt.

[Sqeaky]

@eMi Adding to what sikender said I have seen more than one malicious piece of code posted on the internet. I always rewrite using the concepts provided, so I can be certain what is put into the software is safe.

[p0iz0neR]

This will search and select the text. When it reaches the end and not found anything it will go to start and select the first occurrence. This looks perfect.