CODEWITHSUNDEEP
c#.netip-address
user1608298
user1608298

Reputation: 331

how to convert string to System.Net.IPAddress

how can i convert string to System.Net,IPAddress in C#/.net 3.5

i tried this but i got this error "Cannot convert type 'string' to 'System.Net.IPAddress'"

 public void Form1_Load(object sender, EventArgs e)
    {
        IPHostEntry host;
        string localIP = "?";
        host = Dns.GetHostEntry(Dns.GetHostName());
        foreach (IPAddress ip in File.ReadAllLines("proxy.txt"))
        {
            if (ip.AddressFamily.ToString() == "InterNetwork")
            {
                localIP = ip.ToString();
                textBox1.Text = ip.ToString();
            }
        }

   }

Upvotes: 17

Views: 56758

Answers (6)

Jason Cidras
Jason Cidras

Reputation: 507

One thing you can do is this... In the foreach loop, you need an instance that matches your collection. What I mean is that if you have, for instance, you have a List of strings, like this:

    List<string> lMyList

A programmer cannot iterate through this list with an instance of an int or a double...

    foreach (int lIterator in lMyList) 
    { // code 
    }

This simply will not work and it will throw a syntax error about an "int" isn't a type of "string".

To solve that, you will need to iterate through your list like this

    foreach (string lIterator in lMyList)
    { // code
    }

Now, to your question. An IPAddress is it's own class and type. One cannot simply make it a type of string. However, there are ways to get around this. Explicitly convert a string to an IP address. But, you will need to iterate over your list first.

    foreach (string lLine in File.ReadAllLines("proxy.txt"))
    {
        // Code In Here
    }

This will iterate all the lines in the text file. Since it's a text file, it returns a list of strings. In order to iterate over a list of strings, a programmer needs a string local variable to iterate over it.

Next, you will need to parse the current string to a local IP Address instance. There are a few ways of doing this, 1) You can simply Parse (System.Net.IPAddress.Parse()) the string, or you can TryParse (IPAddress.TryParse()) a string into an IPAddress.

    Method One:
    // This will parse the current string instance to an IP Address instance
    IPAddress lIPAddress = IPAddress(lLine);

    Method Two:
    IPAddress lIPAddress; // Local instance to be referenced
    // At runtime, this will "Try to Parse" the string instance to an IP Address.
    // This member method returns a bool, which means true or false, to say,
    // "Hey, this can be parsed!". Your referenced local IP Address instance would
    // have the value of the line that was parsed.
    if (IPAddress.TryParse(lLine, out lIPAddress)) 
    {
        // Code
    }

Okay, now we got that out of the way. Lets finish this up.

    // Iterates over the text file.
    foreach (string lLine in File.ReadAllLines("proxy.txt"))
    {
        // Create a local instance of the IPAddress class. 
        IPAddress lIPAddress;
        // Try to Parse the current string to the IPAddress instance.
        if (IPAddress.TryParse(lLine, out lIPAddress))
        {
            // This means that the current line was parsed.
            // Test to see if the Address Family is "InterNetwork"
            if (string.Equals("InterNetwork", lIPAddress.AddressFamily.ToString()))
            {
                TextBox1.Text = lIPAddress.ToString();
            }
        }
    }

I hope this helps!

Upvotes: 0

Steven Doggart
Steven Doggart

Reputation: 43743

The IPAddress.Parse method accepts a string.

foreach (string line in File.ReadAllLines("proxy.txt"))
{
    IPAddress ip = IPAddress.Parse(line);
    // ...
}

Upvotes: 6

Timbo
Timbo

Reputation: 28050

You can use IPAddress.Parse to do that.

Upvotes: 1

Richard
Richard

Reputation: 30618

foreach (IPAddress ip in File.ReadAllLines("proxy.txt").Select(s => IPAddress.Parse(s))) {
    // ...
}

Upvotes: 3

Oded
Oded

Reputation: 498904

Use the static IPAddress.Parse method to parse a string into an IPAddress:

foreach (var ipLine in File.ReadAllLines("proxy.txt"))
{
    var ip = IPAddress.Parse(ipLine);
    if (ip.AddressFamily.ToString() == "InterNetwork")
    {
        localIP = ip.ToString();
        textBox1.Text = ip.ToString();
    }
}

If the lines in the file are not always valid IP addresses, you may want to consider using TryParse to avoid any exceptions being thrown.

Upvotes: 25

TrizZz
TrizZz

Reputation: 1200

You can use IPAddress.Parse Method for example:

private static void parse(string ipAddress)
  {
    try
    {
      IPAddress address = IPAddress.Parse(ipAddress);
    }

Upvotes: 2

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