70-505 全真模擬試験 DEMO

問題13: You are creating a Windows Forms application for a courier company by using the .NET Framework 3.5.
You create a form that allows customers to track the progress of their shipments.
The form contains the following elements:
- A text box named txtTN that allows users to enter a tracking number
- An ErrorProvider control named ErrorProvider1 that informs users of an invalid tracking number
- A function named ValidTrackingNumber that validates tracking numbers
You need to ensure that the txtTN text box is validated, which code segment should you use?
A. private void txtTN_Validating(object sender, CancelEventArgs e) {
if (!ValidTrackingNumber(txtTN.Text)){
errorProvider1.SetError(txtTN, "InvalidTracking Number")
e.Cancel = true;
}
else
errorProvider1.SetError(txtTN, "")
}
B. private void txtTN_Validating(object sender, CancelEventArgs e){
if (!ValidTrackingNumber(txtTN.Text))
errorProvider1.SetError(txtTN, "Invalid Tracking Number")
else{
errorProvider1.SetError(txtTN, "")
e.Cancel = true
}
}
C. private void txtTN_Validated(object sender, EventArgs e){
if (!ValidTrackingNumber(txtTN.Text))
errorProvider1.SetError(txtTN, "Invalid Tracking Number")
else{
errorProvider1.SetError(txtTN, "")
txtTN.Focus()
}
}
D. private void txtTN_Validated(object sender, EventArgs e){
if (!ValidTrackingNumber(txtTN.Text))
{
errorProvider1.SetError(txtTN, "InvalidTracking Number")
txtTN.Focus()
}
else
errorProvider1.SetError(txtTN, "")
}
正解: A