Multiple strings in an SQL

I've got a GridView, a datasource, 2 textboxes and a button. If I choose to bind the GridView to the datasource the correct data is shown. But if I modify the datasource and chooses the TextBoxes as Parameter Controls it doesn't work out as I expected.

Can I please have a step-by-step response which will work? And expecially if one if the TextBoxes eguals nothing/null. Because this is very important, too, and that part doesn't work either.

Did you mean choosing a datasource for the textbox, and display data from datasource in the textbox? Textbox can only display 1 cell, if you want to display multiple lines, consider using listbox.