Highlight entire line in Richtextbox if a text is present

I'm trying to highlight a particular line in my RichTextBox as shown in figure.

int ptrsize = 10;
int* linenum; 
for (int i = 0; i < ptrsize; i++)
{           
    int value = (linenum[i]) * 10;
    string searchText = value.ToString();
    int indexToText = richTextBox.Find(searchText);
    int endIndex = searchText.Length;
    richTextBox.Select(indexToText, endIndex);
    richTextBox.SelectionColor = Color.Blue;
}

If a text is present (i.e. 2010), i want to highlight the entire line.

2010 19.5 7.37 105 0.67 0.26 0.69