How to Update a value in Dictionary based on Key IN C#

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Hi all,
can any one give me a sample how to update a value in dictionary based upon the key.

I have a collection of frames in a Dictionary

public Dictionary<int,frames> FrameID=new Dictionary<int,> ();
System .IO .DirectoryInfo myimagesdir=new System .IO.DirectoryInfo(@".\\tmp");
			
foreach(System .IO.FileInfo myimagesfile in myimagesdir.GetFiles("*.jpg"))
{
frameno=frameno+1;
FrameID.Add(frameno,new Frames());
}

Now i want to update frames based on the key. like for key=1 i want to add different frame(which is edited one).
how can i update old frame with new edited frame .

Thanks,

Posted 21-Oct-11 1:18am

KiranBabu M

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3 solutions

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Shmuel Zang · Accepted Answer · 2011-10-21T01:28:00

Solution 2

Assumption: i is the key and, newFrame is the new value.

You can do it like the follwing:

C#

if (FrameID.ContainsKey(i))
{
    FrameID.Remove(i);
}

FrameID.Add(i, newFrame);

Posted 21-Oct-11 1:28am

Shmuel Zang

Updated 21-Oct-11 1:35am

v2

Mehdi Gholam · Accepted Answer · 2011-10-21T01:27:00

Solution 1

C#

frames f = null;
if(FrameID.TryGetValue(frameno, out f))
{
   // frameno is in dictionary
   FrameID[frameno] = val;
}
else 
   FrameID.Add(frameno, val);

Posted 21-Oct-11 1:27am

Mehdi Gholam

OriginalGriff · Accepted Answer · 2011-10-21T01:35:00

Just treat it as an array.
This uses strings, but that's just because it is easier to see what is going on.

C#

Dictionary<int, string> dict = new Dictionary<int, string>();
dict.Add(0, "zero");
dict.Add(1, "one");
dict.Add(2, "two");
foreach (KeyValuePair<int, string> kvp in dict)
    {
    Console.WriteLine("{0} : {1}", kvp.Key, kvp.Value);
    }
dict[1] = "une";
foreach (KeyValuePair<int, string> kvp in dict)
    {
    Console.WriteLine("{0} : {1}", kvp.Key, kvp.Value);
    }