如何使用凭据，例如：login.cs中的员工社会保险号以另一种形式反映出来，例如：expense.cs无需手动键入

如何解决如何使用凭据，例如：login.cs中的员工社会保险号以另一种形式反映出来，例如：expense.cs无需手动键入

这是具有用户在登录时输入的凭据的登录页面。

private void simpleButton1_Click(object sender,EventArgs e)
{
    try
    {
        string myConnection = "datasource = localhost;database = imprest system;port = 3306;username = root;password = ''";
        MysqLConnection myConn = new MysqLConnection(myConnection);
        MysqLCommand SelectCommand = new MysqLCommand("select * from user where **employeeSSN = '" + employeeSSN_txt.Text + "'** and Password = '" + pass_txt.Text + "'",myConn);

        MysqLDataReader myreader;
        myConn.open();
        myreader = SelectCommand.ExecuteReader();
        int count = 0;
        while (myreader.Read())
        {
            count = count + 1;
        }
        if (count == 1)
        {
            Dashboard dashboard = new Dashboard();
            dashboard.ShowDialog();
        }
        else if (count > 1)
        {
            XtraMessageBox.Show("Error logging in");
        }
        else
        {
            XtraMessageBox.Show("Incorrect Username and Password.Try Again");
        }
    }
    catch (Exception ex)
    {
        XtraMessageBox.Show(ex.Message);
    }
}

我想使用Employee社保号而无需手动输入的代码部分。

private void simpleButton1_Click(object sender,EventArgs e)
{
    string myConnection = "datasource = localhost;database = imprest system;port = 3306;username = root;password = ''";
    MysqLConnection myConn = new MysqLConnection(myConnection);
    MysqLCommand InsertCommand = new MysqLCommand("insert into expenseaccount where ExpenseType = '" + Expense_txt + "' and Amount = '" + Amount_txt + "' and **employeeSSN =** ",myConn);

    MysqLDataReader myreader;
    myConn.open();
    myreader = InsertCommand.ExecuteReader();
}