使用C＃的SQLlite中的.ExecuteNonQuerry（）错误

Question

searching in google, and in many posts here, but still I have not been able to find a solution for my program. so the code:

      var str1 = flatComboBox1.SelectedItem.ToString();
            var str2 = flatNumeric2.Value.ToString();
            var str3 = flatTextBox4.Text.ToString();
        var str4 = flatTextBox7.Text = ToString();
            SQLiteCommand SelectCommand = new SQLiteCommand("UPDATE Produkte  SET Emri='"+ str1 +"', Sasia='" + str2 + "',Cmimi ='" + str3 + "', CmimiB='" +str4+"'  WHERE Emri='" + str1 + "'");

        try
        {
            connectionstring.Open();

            SelectCommand.ExecuteNonQuery(); // <--- Line 65 and the error

            connectionstring.Close();
        }
        catch (Exception ex) {
            MessageBox.Show(ex.ToString());
        }

This is the error I get.

how to fix this? I've tried many things over the time, and still looks like nothing can fix it.

Answer 1

You might want to try to use a parameterized statement to avoid possible issues with apostrophes in C# string variables when they become part of the SQL query.

For example:

  SQLiteCommand SelectCommand = new SQLiteCommand("UPDATE Produkte  SET Emri = @Emri, Sasia= @Sasia, Cmimi = @Cmimi, CmimiB = @CmimiB  WHERE Emri = @Emri");

SelectCommand.Parameters.AddWithValue("@Emri", str1);
SelectCommand.Parameters.AddWithValue("@Sasia", str2);

Or you can do:

SelectCommand.Parameters.Add(new SQLiteParameter("@Emri", str1));

And so on, for all parameters.