ActiveReports 12
Find Method (RichTextBox)
Example 

GrapeCity.ActiveReports.v12 Assembly > GrapeCity.ActiveReports.SectionReportModel Namespace > RichTextBox Class : Find Method
Searches for text in the content of the RichTextBox control.
Overload List
OverloadDescription
Searches the text of a RichTextBox control for the first instance of a character from a list of characters.  
Searches the text of the RichTextBox control for a string.  
Searches the text in the RichTextBox control for a specified string starting at a specified location.  
Searches the text in the RichTextBox control for a specified string starting at a specified location and with specific options applied to the search.  
Example
Private void Detail_Format(object sender, System.EventArgs eArgs)
{
    if (this.RichTextBox1.Find("past due")!= -1)
    {
        this.txtPayNow.Visible=true;
    }
    else
    {
        this.txtPayNow.Visible=false;
    }
}
Private Sub Detail_Format(ByVal sender As Object, ByVal e As System.EventArgs) Handles Detail.Format
    If Not Me.RichTextBox1.Find("past due") = -1 Then
        Me.txtPayNow.Visible = True
    Else
        Me.txtPayNow.Visible = False
    End If
End Sub
See Also

Reference

RichTextBox Class
RichTextBox Members