Confused by the NameValueCollection

  • Thread starter Thread starter anon
  • Start date Start date
A

anon

I need a little clarity in the NameValueCollection.

Within the MSDN .NET 1.1 Framework help is says:

"This collection is based on the NameObjectCollectionBase class.
However, unlike the
NameObjectCollectionBase, this class stores multiple string values under
a single key."



What does this REALLY MEAN?

IS THIS CORRECT WAY?
EXAMPLE #1
Index Key Value
0 a "alpha"
1 b "beta"
2 c "charlie"
3 c "clifford"


OR does it mean
EXAMPLE #2
Index Key Value
0 a "alpha"
1 b "beta"
2 c "charlie", "clifford"


see how I am confused?
 
Hey anon

If you add two or more values for the same key to a NameValueCollection, the value for that key will contain a comma-separated list of the values. For example

NameValueCollection c = new NameValueCollection()
c.Add("a", "1")
c.Add("a", "2")
Console.WriteLine(c["a"]); // Outputs "1,2

Regards, Jakob
 
Example 2.

NameValueCollection nvc=new NameValueCollection();

nvc.Add("A","Alpha");

nvc.Add("B","Beta");

nvc.Add("C","Charlie");

nvc.Add("C","Chumpkin");

for(int n=0; n<nvc.Count; n++)

Console.WriteLine(nvc[n]);

foreach(string s in nvc.Keys)

Console.WriteLine(nvc);


--
Bob Powell [MVP]
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Hi,

see the documentaion for NameValueCollection's Add method. It says:

"If the specified key already exists in the target NameValueCollection
instance, the specified value is added to the existing comma-separated list
of values associated with the same key in the target NameValueCollection
instance."
 
What if the values have a "comma" in them? How is the comma-separated list
going to know where the next "REAL" value is?
 
They are all the real value. The values share a key.

--
Bob Powell [MVP]
Visual C#, System.Drawing

Image transition effects, automatic persistent configuration and
design time mouse operations all in April's issue of Well Formed
http://www.bobpowell.net/wellformed.htm

Answer those GDI+ questions with the GDI+ FAQ
http://www.bobpowell.net/gdiplus_faq.htm

The GDI+ FAQ RSS feed: http://www.bobpowell.net/faqfeed.xml
Windows Forms Tips and Tricks RSS: http://www.bobpowell.net/tipstricks.xml
Bob's Blog: http://royo.is-a-geek.com/siteFeeder/GetFeed.aspx?FeedId=41
 
What if the values have a "comma" in them? How is the
comma-separated list going to know where the next "REAL" value
is?
Click to expand...


Use the GetValues() method:


using System;
using System.Collections.Specialized;

namespace ExampleNamespace
{
public class TestForm
{
[STAThread]
public static void Main()
{
NameValueCollection nvc = new NameValueCollection();

nvc.Add("A","Alpha");
nvc.Add("B","Beta");
nvc.Add("C","Charlie 1,Charlie sub-1");
nvc.Add("C","Charlie 2");

foreach(string key in nvc.Keys)
{
Console.WriteLine("Key = {0}", key);

// A key may point to multiple values. Process
// the values individually by using the GetValues method.

foreach(string value in nvc.GetValues(key))
Console.WriteLine(" Value = {0}", value);
}
}
}
}


Hope this helps.

Chris.
 
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