Question

I am constructing a URL at runtime. So far I have done like

public string BuildURLAndNavigate(CodeType codeType)
{    
    string vURL = string.Empty; 

    string mstrNavServer = "http://some.com/nav";
    vURL = ConcatenateString(mstrNavServer , "/somepage.asp?app=myapp");

    //Build Code Type
    switch (codeType)
    {
    case CodeType.Series:
        vURL = ConcatenateString(vURL , "&tools=ser");
        break; 
    case CodeType.DataType:
        vURL = ConcatenateString(vURL , "&tools=dt");
        break;
    }

    //build version 
    string VER_NUM = "5.0";
    vURL = ConcatenateString(vURL , ConcatenateString("&vsn=" , VER_NUM));         
    return vURL;
    }

    private string ConcatenateString(string expression1, string expression2)
    {
        return string.Concat(expression1 + expression2);
    }

But I am not happy with the one I am doing.

I am sure that there is definitely a best practice / better approach than this.

Kindly help me out in guiding for the same.

Thanks

Answer 1

Never build urls using strings, string builders, string concatenations.

You could start by defining a custom collection which will take care of properly URL encoding any value being added to it:

public class HttpNameValueCollection : NameValueCollection
{
    public override void Add(string name, string value)
    {
        base.Add(name, HttpUtility.UrlEncode(value));
    }

    public override string ToString()
    {
        return string.Join("&", Keys.Cast<string>().Select(
            key => string.Format("{0}={1}", key, this[key])));
    }
}

And then simply:

public string BuildURLAndNavigate()
{
    var uriBuilder = new UriBuilder("http://some.com/nav/somepage.asp");
    var values = new HttpNameValueCollection();
    values.Add("app", "myapp");

    switch (codeType)
    {
        case CodeType.Series:
            values.Add("tools", "ser");
            break;
        case CodeType.DataType:
            values.Add("tools", "dt");
            break;
    }

    // You could even do things like this without breaking your urls
    values.Add("p", "http://www.example.com?p1=v1&p2=v2");


    string VER_NUM = "5.0";
    values.Add("vsn", VER_NUM);
    uriBuilder.Query = values.ToString();
    return uriBuilder.ToString();
}