Shops loading error

[someone]

Problem here:

this.Reader = MySqlCommand.ExecuteReader();
this.Reader.Read();
this.textBox_name.Text = this.Reader["a_keeper_idx"].ToString();

if there are no  rows  from the reader  it will return false, if it will try to read the a_keeprer_idx from the reader, it will throw an exception.

 

Try something like this

this.Reader = MySqlCommand.ExecuteReader();
if(this.Reader.Read()){
   this.textBox_name.Text = this.Reader["a_keeper_idx"].ToString();
}
this.Reader.Close();
Try to use this.Reader.Close(); before this.Reader.Dispose();

 

Another problem is this:

string text = this.Shops.SelectedItem.ToString();
MySqlCommand.CommandText = string.Concat(new string[]
            {
                "select * from `",
                textBox_db.Text,
                "`.`t_shop` where a_keeper_idx=",
                text,
                ";"
            });
this.Shops.SelectedItem.ToString() is a string not a index where in your query you look for a index:

"select * from `t_shop` where a_keeper_idx=Master of Monster Combo;"
Which it should be something like this(123 is the ID of the NPC):

"select * from `t_shop` where a_keeper_idx=123;"
Why are you opening so many connections?