why does it freeze?

my objective is to make my button flexible depending on what is currently the value of my combo box, but the problem is when i run my program on that particular event it freezes, is there something wrong with my syntax or my computer is just slow? 

private void cmbOperation_SelectedIndexChanged(object sender, EventArgs e)
{
    string selected = (string)cmbOperation.SelectedItem;

    while (selected == "ADD")
    {
        txtID.ReadOnly = true;
        txtLName.ReadOnly = false;
        txtFName.ReadOnly = false;
        txtMI.ReadOnly = false;
        txtGender.ReadOnly = false;
        txtAge.ReadOnly = false;
        txtContact.ReadOnly = false;

        btnOperate.Text = "ADD CLIENT";
    }
}
private void btnOperation_Clicked(object sender, EventArgs e)
{            
    if (cmbOperation.SelectedItem.Equals("ADD"))
    {
        string constring = "datasource=localhost;port3306;username=root";
        string Query = "insert into mybusiness.client_list (LastName,FirstName,MI,Gender,Age,Contact) values('" + this.txtLName.Text + "','" + this.txtFName.Text + "','" + this.txtMI.Text + "','" + this.txtGender.Text + "','" + this.txtAge.Text + "','" + txtContact.Text + "' ;";
        MySqlConnection conDB = new MySqlConnection(constring);
        MySqlCommand cmDB = new MySqlCommand(Query, conDB);
        MySqlDataReader myReader;

        try
        {
            conDB.Open();
            myReader = cmDB.ExecuteReader();
                MessageBox.Show("Client Information has been added to the list");
            while(myReader.Read())
            {
            }
        }
        catch(Exception ex)
        {
            MessageBox.Show(ex.Message);
        }          
    }
}
Jon Skeet
people
quotationmark

You're not changing the condition for your while loop - so if it's ever true, it will always be true:

string selected = (string)cmbOperation.SelectedItem;

while (selected == "ADD")
{
    // Code that doesn't change the value of selected
}

There are other significant problems with your code, however:

  • You're performing database operations on the UI thread. That will hang the UI until the operation has completed. It would be better to use async/await and asynchronous database operations
  • Your code is vulnerable to SQL injection attacks because you're building the SQL from the values instead of using parameterized SQL. Fix this first.
  • You're calling ExecuteReader to perform an insert operation. Use ExecuteNonQuery instead - ExecuteReader is designed for queries, and your code isn't querying anything.
  • You should use using statements for the connection and command, so they are closed automatically when execution leaves the scope of the using statement - currently your connection will hang around until it is finalized and garbage collected; this can lead to hangs.

people

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