how to show the data in gridview by clicking the search button

Create a parameterized query or stored procedure that returns the Person information based on the PersonID passed from your front-end. Execute this query from your code-behind (the Search button even) passing in the value entered from the txtID textbox. Return the result, and then assign that result to your GridView. Below is a simple example of the stored procedure.

CREATE PROCEDURE GetPersonByID
(
	@PersonID INT
)
SELECT * FROM Person
WHERE
	PersonID = @PersonID