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SqlConnectionStringBuilder.TryGetValue Method

Retrieves a value corresponding to the supplied key from this SqlConnectionStringBuilder.

Namespace:  System.Data.SqlClient
Assembly:  System.Data (in System.Data.dll)

'Declaration
Public Overrides Function TryGetValue ( _
	keyword As String, _
	<OutAttribute> ByRef value As Object _
) As Boolean

Parameters

keyword
Type: System.String

The key of the item to retrieve.

value
Type: System.Object

The value corresponding to keyword.

Return Value

Type: System.Boolean
true if keyword was found within the connection string; otherwise, false.

ExceptionCondition
ArgumentNullException

keyword contains a null value (Nothing in Visual Basic).

The TryGetValue method lets developers safely retrieve a value from a SqlConnectionStringBuilder without needing to verify that the supplied key name is a valid key name. Because TryGetValue does not raise an exception when you call it, passing in a nonexistent key, you do not have to look for a key before retrieving its value. Calling TryGetValue with a nonexistent key will place the value null (Nothing in Visual Basic) in the value parameter.

The following example demonstrates the behavior of the TryGetValue method.

Imports System.Data.SqlClient

Module Module1
    Sub Main()
        Dim builder As New SqlConnectionStringBuilder
        builder.ConnectionString = GetConnectionString()

        ' Call TryGetValue method for multiple 
        ' key names. Note that these keys are converted 
        ' to well-known synonynms for data retrieval.
        DisplayValue(builder, "Data Source")
        DisplayValue(builder, "Trusted_Connection")
        DisplayValue(builder, "InvalidKey")
        DisplayValue(builder, Nothing)

        Console.WriteLine("Press any key to continue.")
        Console.ReadLine()
    End Sub 

    Private Sub DisplayValue( _
     ByVal builder As SqlConnectionStringBuilder, ByVal key As String)
        Dim value As Object = Nothing 

        ' Although TryGetValue handles missing keys, 
        ' it doesn't handle passing in a null (Nothing in Visual Basic) 
        ' key. This example traps for that particular error, but 
        ' passes any other unknown exceptions back out to the 
        ' caller.  
        Try 
            If builder.TryGetValue(key, value) Then
                Console.WriteLine("{0}='{1}' ", key, value)
            Else
                Console.WriteLine("Unable to retrieve value for '{0}'", key)
            End If 
        Catch ex As ArgumentNullException
            Console.WriteLine("Unable to retrieve value for null key.")
        End Try 
    End Sub 

    Private Function GetConnectionString() As String 
        ' To avoid storing the connection string in your code, 
        ' you can retrieve it from a configuration file.  
        Return "Server=(local);Integrated Security=SSPI;" & _
          "Initial Catalog=AdventureWorks" 
    End Function 
End Module

The sample displays the following results:

Data Source=(local)
Trusted_Connection=True
Unable to retrieve value for 'InvalidKey'
Unable to retrieve value for null key.

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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