How to check that a string is a proper URL

[teguh123]

That starts with http://

Using regular expression

Can I see a code

Thanks

[RhinoBull]

The easy way is to attempt to navigate to that place - if success then url is valid.
You may parse it but there could still be margin for error...

[Hack]

How about something simple like

If Left(Text1.Text, 7) <> "http://" Then
   MsgBox "Invalid URL"
End If

[RobDog888]

Why user regex when its simple to use string functions like hack posted?

What are the reqquirements for the urls? "https://", "ftp://", "ftps://" etc?

[RhinoBull]

So, what happens if all you have is this:

"http://www"

It does have "http" in it but it still ain't valid... As I said best way to validate url is to try to navigate there.

[teguh123]

Well because I have 10000 URL to check and I want to do it quickly. Surfing them one by one is not a good idea.

Doesn't have to be regex but regex seems to be the way to go.

Let's see we can make sure it has only one http:// or https://

Then we look at the content between http:// and the next /

Then we look that those between and after that consists of numbers and letters allowed in a URL

There has to be regex for this one already.

[leinad31]

Check left side as already mentioned. Check if there are unescaped characters, e.g. spaces instead of %20. URL may then be syntactically valid... but real validity can only be tested by navigation.

[RobDog888]

Well what is it that you want to accomplish? Check for valid syntax only or check for valid syntax and know the url points to a valid site?

[teguh123]

Only valid syntax.

Of course the only way to know that the URL is valid is by actually visiting the URL.

No. Just valid syntax.

[Merri]

Google