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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)
public override bool TryGetValue(
	string keyword,
	out Object value
)

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.


using System.Data.SqlClient;

using System;
using System.Data.SqlClient;


class Program
{
    static void Main()
    {
        SqlConnectionStringBuilder builder = 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, null);

        Console.WriteLine("Press any key to continue.");
        Console.ReadLine();
    }

    private static void DisplayValue(
        SqlConnectionStringBuilder builder, string key)
    {
        object value = null;

        // Although TryGetValue handles missing keys,
        // it doesn't handle passing in a null
        // key. This example traps for that particular error, but
        // passes any other unknown exceptions back out to the
        // caller. 
        try
        {
            if (builder.TryGetValue(key, out value))
            {
                Console.WriteLine("{0}='{1}'", key, value);
            }
            else
            {
                Console.WriteLine("Unable to retrieve value for '{0}'", key);
            }
        }
        catch (ArgumentNullException)
        {
            Console.WriteLine("Unable to retrieve value for null key.");
        }
    }

    private static string GetConnectionString()
    {
        // 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";
    }
}


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, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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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