DataGridView search function not working perfectly

Question

Sir,

 

I am in Windows form mini project. My issue is search function in DataGridView with a TextBox is not working perfectly; gridview is filling , but with a duplicate row.

 

this is SQL Query : -

 

c# code :-

 

 

 

 

 

 result before search function:-

 

 

 and the result after search function : -