How to search in crystal report viewer by text box

I made  this code to search in gridview how can i make it to serch in crystal report  viewer

lblfield.SelectedValue come from radio button list

The method  

grid.DataSource = U.Search(lblfield.SelectedValue, txtsearch.Text);
grid.DataBind();

public DataTable Search(string Field, string Value)
    {
        string query = string.Format("Select UserID, UserTypeID, UserName, Password, FirstName, MiddleName from Users where {0} like'%{1}%'  ", Field, Value);
        return Search(query);
    }