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DbConnectionStringBuilder Class

Provides a base class for strongly typed connection string builders.

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

Public Class DbConnectionStringBuilder _
	Implements IDictionary, ICollection, IEnumerable, ICustomTypeDescriptor
Dim instance As DbConnectionStringBuilder

The DbConnectionStringBuilder class provides the base class from which the strongly typed connection string builders (SqlConnectionStringBuilder, OleDbConnectionStringBuilder, and so on) derive. The connection string builders let developers programmatically create syntactically correct connection strings, and parse and rebuild existing connection strings.

The DbConnectionStringBuilder has been defined in a database-agnostic manner. Because of the addition of the System.Data.Common namespace, developers require a base class against which they can program in order to build connection strings that can work against an arbitrary database. Therefore, the DbConnectionStringBuilder class lets users assign arbitrary key/value pairs and pass the resulting connection string to a strongly typed provider. All the data providers that are included as part of the .NET Framework provide a strongly typed class that inherits from DbConnectionStringBuilder: SqlConnectionStringBuilder, OracleConnectionStringBuilder, OdbcConnectionStringBuilder, and OleDbConnectionStringBuilder.

The developer can build, assign, and edit connection strings for any arbitrary provider. For providers that support specific key/value pairs, the connection string builder provides strongly typed properties corresponding to the known pairs. In order to support providers that require the ability to support unknown values, developers can also supply arbitrary key/value pairs.

The DbConnectionStringBuilder class implements the ICustomTypeDescriptor interface. This means that the class works with Visual Studio designers at design time. When developers use the designer to build strongly typed DataSets and strongly typed connections within Visual Studio, the strongly typed connection string builder class will display the properties associated with its type and will also have converters that can map common values for known keys.

Developers needing to create connection strings as part of applications can use the DbConnectionStringBuilder class or one of its strongly typed derivatives to build and modify connection strings. The DbConnectionStringBuilder class also makes it easy to manage connection strings stored in an application configuration file.

Developers can create connection strings using either a strongly typed connection string builder class, or they can use the DbConnectionStringBuilder class. The DbConnectionStringBuilder performs no checks for valid key/value pairs. Therefore, it is possible using this class to create invalid connection strings. The SqlConnectionStringBuilder supports only key/value pairs that are supported by SQL Server; trying to add invalid pairs will throw an exception.

Both the Add method and Item property handle tries to insert malicious entries. For example, the following code correctly escapes the nested key/value pair:

[Visual Basic]

Dim builder As New System.Data.Common.DbConnectionStringBuilder
builder("Data Source") = "(local)"
builder("integrated sSecurity") = True
builder("Initial Catalog") = "AdventureWorks;NewValue=Bad"


System.Data.Common.DbConnectionStringBuilder builder = 
    new System.Data.Common.DbConnectionStringBuilder();
builder["Data Source"] = "(local)";
builder["integrated Security"] = true;
builder["Initial Catalog"] = "AdventureWorks;NewValue=Bad";

The result is the following connection string that handles the invalid value in a safe manner:

data source=(local);integrated security=True;
initial catalog="AdventureWorks;NewValue=Bad"

The following console application builds two connection strings, one for a Microsoft Jet database, and one for a Microsoft SQL Server 2005 database. In each case, the code uses a generic DbConnectionStringBuilder class to create the connection string, and then passes the ConnectionString property of the DbConnectionStringBuilder instance to the constructor of the strongly type connection class. This is not required; the code could also have created individual strongly typed connection string builder instances. The example also parses an existing connection string, and demonstrates various ways of manipulating the connection string's contents.

Sub Main()
    Dim builder As New DbConnectionStringBuilder()
    builder.ConnectionString = "Data Source=c:\MyData\MyDb.mdb"
    builder.Add("Provider", "Microsoft.Jet.Oledb.4.0")
    builder.Add("Jet OLEDB:Database Password", "*******")
    builder.Add("Jet OLEDB:System Database", _

    ' Set up row-level locking.
    builder.Add("Jet OLEDB:Database Locking Mode", 1)

    ' Note that the DbConnectionStringBuilder class  
    ' is database agnostic, and it's possible to  
    ' build any type of connection string using  
    ' this class. 
    ' Notice that the ConnectionString property may have been  
    ' formatted by the DbConnectionStringBuilder class. 

    Dim oledbConnect As New _

    ' Use the same DbConnectionStringBuilder to create  
    ' a SqlConnection object.
    builder.Add("integrated security", True)
    builder.Add("Initial Catalog", "AdventureWorks")
    builder.Add("Data Source", "(local)")

    Dim sqlConnect As New SqlConnection(builder.ConnectionString)

    ' Pass the DbConnectionStringBuilder an existing  
    ' connection string, and you can retrieve and 
    ' modify any of the elements.
    builder.ConnectionString = _
        "server=(local);user id=*******;" & _
        "password=*******;initial catalog=AdventureWorks"
    builder.Item("Server") = "."
    builder.Remove("User ID")

    ' Note that calling Remove on a nonexistent item doesn't 
    ' throw an exception.

    ' The Item property is the default for the class,  
    ' and setting the Item property adds the value if  
    ' necessary.
    builder("Integrated Security") = True
    builder.Item("User ID") = "Hello"

    Console.WriteLine("Press Enter to finish.")
End Sub

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

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

.NET Framework

Supported in: 3.5, 3.0, 2.0