Artikel
11/18/2011

Guid.TryParseExact Method

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Converts the string representation of a GUID to the equivalent Guid value, provided that the string is in the specified format.

Namespace: System
Assembly: mscorlib (in mscorlib.dll)

Syntax

'Declaration
Public Shared Function TryParseExact ( _
    input As String, _
    format As String, _
    <OutAttribute> ByRef result As Guid _
) As Boolean

public static bool TryParseExact(
    string input,
    string format,
    out Guid result
)

Parameters

input
Type: System.String
The GUID to convert.

format
Type: System.String
One of the following specifiers that indicates the exact format to use when interpreting input: "N", "D", "B", "P", or "X".

result
Type: System.Guid%
When this method returns, contains the value that is equivalent to the GUID contained in input if the conversion succeeded, or Guid.Empty if the conversion failed.

Return Value

Type: System.Boolean
true if the parse operation was successful; otherwise, false.

Remarks

This method returns false if input is nulla null reference (Nothing in Visual Basic) or not in a recognized format, and does not throw an exception.

The following table shows the accepted format specifiers for the format parameter. "0" represents a digit; hyphens ("-"), braces ("{", "}"), and parentheses ("(", ")") appear as shown.

Specifier	Format of the input parameter
N	32 digits: 00000000000000000000000000000000
D	32 digits separated by hyphens: 00000000-0000-0000-0000-000000000000
B	32 digits separated by hyphens, enclosed in braces: {00000000-0000-0000-0000-000000000000}
P	32 digits separated by hyphens, enclosed in parentheses: (00000000-0000-0000-0000-000000000000)
X	Four hexadecimal values enclosed in braces, where the fourth value is a subset of eight hexadecimal values that is also enclosed in braces: {0x00000000,0x0000,0x0000,{0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00}}

Examples

The following example calls the ToString method with each of the supported format specifiers to generate an array of strings that represent a single GUID. These are then passed to the TryParseExact method, which successfully parses the string that conforms to the "B" format specifier.

Module Example
   Public Sub Demo(outputBlock As System.Windows.Controls.TextBlock)
      ' Define an array of all format specifiers.
      Dim formats() As String = { "N", "D", "B", "P", "X" }
      Dim guid As Guid = Guid.NewGuid()
      ' Create an array of valid Guid string representations.
      Dim stringGuids(formats.Length - 1) As String
      For ctr As Integer = 0 To formats.Length - 1
         stringGuids(ctr) = guid.ToString(formats(ctr))
      Next

      ' Try to parse the strings in the array using the "B" format specifier.
      For Each stringGuid In stringGuids
         Dim newGuid As Guid
         If Guid.TryParseExact(stringGuid, "B", newGuid) Then
            outputBlock.Text += String.Format("Successfully parsed {0}", 
                                              stringGuid) + vbCrLf
         Else
            outputBlock.Text += String.Format("Unable to parse '{0}'", 
                                              stringGuid) + vbCrLf
         End If   
      Next      
   End Sub
End Module
' The example displays the following output:
'    Unable to parse 'c0fb150f6bf344df984a3a0611ae5e4a'
'    Unable to parse 'c0fb150f-6bf3-44df-984a-3a0611ae5e4a'
'    Successfully parsed {c0fb150f-6bf3-44df-984a-3a0611ae5e4a}
'    Unable to parse '(c0fb150f-6bf3-44df-984a-3a0611ae5e4a)'
'    Unable to parse '{0xc0fb150f,0x6bf3,0x44df,{0x98,0x4a,0x3a,0x06,0x11,0xae,0x5e,0x4a}}'

using System;

public class Example
{
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      // Define an array of all format specifiers.
      string[] formats = { "N", "D", "B", "P", "X" };
      Guid guid = Guid.NewGuid();
      // Create an array of valid Guid string representations.
      string[] stringGuids = new string[formats.Length];
      for (int ctr = 0; ctr < formats.Length; ctr++)
         stringGuids[ctr] = guid.ToString(formats[ctr]);

      // Parse the strings in the array using the "B" format specifier.
      foreach (var stringGuid in stringGuids) {
         Guid newGuid;
         if (Guid.TryParseExact(stringGuid, "B", out newGuid))
            outputBlock.Text += String.Format("Successfully parsed {0}\n", stringGuid);
         else 
            outputBlock.Text += String.Format("Unable to parse '{0}'\n", stringGuid);
      }     
   }
}
// The example displays the following output:
//    Unable to parse 'c0fb150f6bf344df984a3a0611ae5e4a'
//    Unable to parse 'c0fb150f-6bf3-44df-984a-3a0611ae5e4a'
//    Successfully parsed {c0fb150f-6bf3-44df-984a-3a0611ae5e4a}
//    Unable to parse '(c0fb150f-6bf3-44df-984a-3a0611ae5e4a)'
//    Unable to parse '{0xc0fb150f,0x6bf3,0x44df,{0x98,0x4a,0x3a,0x06,0x11,0xae,0x5e,0x4a}}'

Version Information

Silverlight

Supported in: 5, 4

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

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