select from database by textbox value in c#

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C#

hello
If a textbox value has changed, how can I select from a database by the new textbox value , not the old value?
using c# and MySql
my code

string constring = "datasource=127.0.0.1;username=root;password=admin";
string Query = "select * from mohamed.usercompany1 where office  =  '" + textBox1.Text + "'  ;";
MySqlConnection conDataBase = new MySqlConnection(constring);
MySqlCommand cmdDataBase = new MySqlCommand(Query, conDataBase);
DataSet DataSet1 = new DataSet();
MySqlDataReader myReader;
try
{
    conDataBase.Open();
    myReader = cmdDataBase.ExecuteReader();
    if (myReader.Read())
    {
        string scode = myReader.GetInt32("techname").ToString();
        textBox1.Text = (string)myReader["techname"];
        comboBox2.Items.Add(scode).ToString();
        listView1.Items.Add(scode).ToString();
        this.Refresh();
    }
}
catch (Exception ex)
{
    MessageBox.Show(ex.Message);
}