Specify a Database Connection at Runtime

• Aug 21, 2020
• 2 minutes to read

Use Predefined Connections

When you use the Data Source Wizard to connect to a database, a connection string is added to the application’s configuration file:

XML

<configuration>  
...  
    <connectionStrings>  
        <add name="dxSample.NWINDConnectionString"  
            connectionString="Data Source=.;Initial Catalog=Northwind;Integrated Security=True" providerName="System.Data.SqlClient" />  
    </connectionStrings>  
...  
</configuration> 

You can use the name attribute to refer to this connection in code:

C#

sqlDataSource1.ConnectionName = "dxSample.NWINDConnectionString";

VB.NET

sqlDataSource1.ConnectionName = "dxSample.NWINDConnectionString"

Create a Connection

Use one of the following options to specify a connection:

1. Specify connection credentials. Create a DataConnectionParametersBase descendant instance (for instance, MsSqlConnectionParameters) and use its new properties to specify credentials, such as the server name, database name, user name, and password.

   C#

   MsSqlConnectionParameters connectionParameters = new MsSqlConnectionParameters("localhost", "nwind.mdf", "username", "password", MsSqlAuthorizationType.SqlServer);  
   SqlDataSource dataSource = new SqlDataSource();  
   dataSource.ConnectionName = "nwindConnection";  
   dataSource.ConnectionParameters = connectionParameters; 
   

   VB.NET

   Dim connectionParameters As New MsSqlConnectionParameters("localhost", "nwind.mdf", "username", "password", MsSqlAuthorizationType.SqlServer)
   Dim dataSource As New SqlDataSource()
   dataSource.ConnectionName = "nwindConnection"
   dataSource.ConnectionParameters = connectionParameters
   

2. Specify a connection string. Create a CustomStringConnectionParameters class instance and set its ConnectionString property to the connection string.

   C#

   string connectionString = @"XpoProvider=MSSqlServer;Data Source=(local);User ID=username;Password=password;Initial Catalog=database;Persist Security Info=true;";  
   CustomStringConnectionParameters connectionParameters = new CustomStringConnectionParameters(connectionString);  
   SqlDataSource ds = new SqlDataSource(connectionParameters);
   

   VB.NET

   Dim connectionString As String = "XpoProvider=MSSqlServer;Data Source=(local);User ID=username;Password=password;Initial Catalog=database;Persist Security Info=true;"  
   Dim connectionParameters As New CustomStringConnectionParameters(connectionString)  
   Dim ds As New SqlDataSource(connectionParameters)  
   

3. Handle the SqlDataSource.ConfigureDataConnection event and specify the event’s ConnectionParameters. Check the event’s ConnectionName property to identify the connection.

   C#

   private void sqlDataSource1_ConfigureDataConnection(object sender, DevExpress.DataAccess.Sql.ConfigureDataConnectionEventArgs e) {  
   if (e.ConnectionName == "connection1") {  
           e.ConnectionParameters = new Access97ConnectionParameters("../../nwind.mdb", "", "");  
      }  
   }  
   

   VB.NET

   Private Sub sqlDataSource1_ConfigureDataConnection(ByVal sender As Object, ByVal e As DevExpress.DataAccess.Sql.ConfigureDataConnectionEventArgs)  
       If e.ConnectionName = "connection1" Then  
           e.ConnectionParameters = New Access97ConnectionParameters("../../nwind.mdb", "", "")  
       End If  
   End Sub  
   

Tip

Implement the IConnectionProviderService interface and handle its LoadConnection method to customize connections serialized in a report.