CODEWITHSUNDEEP
vb.netvisual-studio-2010
user2302629
user2302629

Reputation: 21

What does this piece of code mean in Visual Basic?

I'm having trouble understanding this code:

SaveFileDialog.InitialDirectory = "C:\"
SaveFileDialog.FileName = "dummy.txt"
SaveFileDialog.Filter = "txt files (*.txt)|*.txt"

If (SaveFileDialog.ShowDialog() = 2) Then
    MsgBox("No dummy has been created", MsgBoxStyle.OkOnly)
Else
    Dim StreamWriter As StreamWriter = File.CreateText(SaveFileDialog.FileName)

I want to know what the "2" means at the beginning of the If statement in this code.

Note: I didn't write this code. This is an example my teacher gave to us.

Upvotes: 1

Views: 172

Answers (2)

User 12345678
User 12345678

Reputation: 7804

When you call the SaveFileDialog.ShowDialog Method a DialogResult is returned. The DialogResult is an enumeration and look like this

public enum DialogResult
{
    None,    // 0
    OK,      // 1
    Cancel,  // 2 !!
    Abort,   // 3
    Retry,   
    Ignore,
    Yes,
    No,      // 7
}

In this case, each enumeration value has an implicit numerical index beginning from zero. In your code sample the code evaluates the DialogResult based on the index instead of the actual enumeration value.

This means that evaluating whether the DialogResult is equal to 2 is equivalent to evaluating whether the DialogResult is equal to DialogResult.Cancel.

This means that when the user presses the cancel button on the dialog window, the MessageBox should be displayed informing the user that they did not select a file.

Upvotes: 3

d.moncada
d.moncada

Reputation: 17402

2 is the dialog result (enumeration value) of the ShowDialog call.

The DialogResult maps to the following enumeration: http://msdn.microsoft.com/en-us/library/system.windows.forms.dialogresult.aspx

So, by checking

If (SaveFileDialog.ShowDialog() = 2) Then
    MsgBox("No dummy has been created", MsgBoxStyle.OkOnly)

the code is validating whether or not the user selected CANCEL on the dialog.

The code should also be written using the enumeration value for the check, which makes it more clear:

If (SaveFileDialog.ShowDialog() = DialogResult.Cancel) Then
    MsgBox("No dummy has been created", MsgBoxStyle.OkOnly)

Upvotes: 1

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