Dictionary - get key by value

Public Xdictionary As New Dictionary(Of String, Integer)
... add values...
.. ABC, 1000..
... DEF, 2935..
....Many Many Values...


Need to get the Key(string) by giving value in a loop.

Something like    
Dim fiaddr As FileInfo() = diaddr.GetFiles("*", SearchOption.TopDirectoryOnly)
For Each scannedFile As FileInfo In fiaddr
      If Xdictionary.ContainsValue(scannedFile.Name) Then
            msgbox ("The Key for file is : " &  Xdictionary.GETKEYFROMVALUE(scannedFile.Name))
      END IF
NEXT

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Basically i need dictionary.ContainsValue to return the key
In vb
LVL 15
Ess KayEntrapenuerAsked:
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it_saigeDeveloperCommented:
Something like this will return your keys that match the value:
Dim keys = dict.Where(Function(pair) pair.Value = match).Select(Function(pair) pair.Key).ToList()
If keys.Count > 0 Then
	' Now you need to decide which matching key you want.
	' If you don't care, you can take the first
	key = keys(0)
End If

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If your values are distinct, then you may be better off just selecting the first *match* as it were:
Dim keys = dict.Where(Function(pair) pair.Value = match).Select(Function(pair) pair.Key).Take(1).ToList()
If keys.Count > 0 Then
	key = keys(0)
End If

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If you are using a dictionary that has keys which are a reference type, you could use this method:
Dim key = dict.Where(Function(pair) pair.Value = match).Select(Function(pair) pair.Key).FirstOrDefault()
If key IsNot Nothing Then
	'Do something with your key...
End If

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Putting it all together:
Dim Xdictionary As New Dictionary(Of FileInfo, String)
Dim diaddr As DirectoryInfo
Dim fiaddr As FileInfo() = diaddr.GetFiles("*", SearchOption.TopDirectoryOnly)
For Each scannedFile As FileInfo In fiaddr
	Dim keys = Xdictionary.Where(Function(pair) pair.Value.Contains(scannedFile.Name)).Select(Function(pair) pair.Key).ToList()
	If keys.Count > 0 Then
		' Now you need to decide which matching key you want.
		' If you don't care, you can take the first
		' key = keys(0)
		MsgBox("The Key for file is : " & keys(0).ToString())
	End If
Next

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-saige-
0
it_saigeDeveloperCommented:
Example -
Imports System.IO

Module Module1
	Sub Main()
		Dim dictionary As New Dictionary(Of String, Integer)
		dictionary.Add("ABC", 123)
		dictionary.Add("DEF", 456)
		dictionary.Add("GHI", 789)
		dictionary.Add("JKL", 0)
		Dim keys = dictionary.Where(Function(pair) pair.Value = 0).Select(Function(pair) pair.Key).ToList()
		If keys.Count > 0 Then
			Console.WriteLine(String.Format("Value - 0, Is Keyed with {0}", keys(0)))
		End If

		keys = dictionary.Where(Function(pair) pair.Value = 123).Select(Function(pair) pair.Key).ToList()
		If keys.Count > 0 Then
			Console.WriteLine(String.Format("Value - 123, Is Keyed with {0}", keys(0)))
		End If

		Console.ReadLine()
	End Sub
End Module

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Produces the following output:Capture.JPG-saige-
0

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Ess KayEntrapenuerAuthor Commented:
Awesome. Thanks.

I actually ended up switch the values and keys by creating the disctionary (of string, string)
because once the item successfully processes, i update the value to completed, from whatever was in it.


But your solution worked great before i made the change.
0
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