使用“嘗試/解析”驗證用戶輸入？

Question

if (!char.TryParse(txtCustomerName.Text, out charCustomerName))  //try to read in Layers from TextBox
{
    MessageBox.Show("Customer Name must be entered.", "Invalid Customer Name");
    return;
}

if (!Decimal.TryParse(txtAmountOwed.Text, out decAmountOwed))  //try to read in Layers from TextBox
{
    MessageBox.Show("Amount Owed must be entered without dollar signs or commas.", "Invalid Amount Owed");
    return;
}

if (!int.TryParse(txtDaysOverdue.Text, out intDaysOverdue))  //try to read in Layers from TextBox
{
    MessageBox.Show("Days Overdue must be entered as a whole number.", "Invalid Days Overdue");
    return;
}

當我運行程序時，它告訴我即使輸入了客戶名也必須輸入。 我該如何改變？

Answer 1

更換

if (!char.TryParse(txtCustomerName.Text, out charCustomerName)) 

與

if (String.IsNullOrEmpty(txtCustomerName.Text)) 

字符代表一個字符