Hi @Alp Koşucu ,Welcome to Q&A.
This is an English forum, please revise your question in English.
Your problem may be caused by this line.
cmd.Parameters.Add("@TUSE", SqlDbType.VarChar, 30).Value = tbTuşe;
Please change "tbTuşe" to "tbTuşe.text".
Best Regards,
Jiale
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