ObjectParameter Constructors

Definition

Namespace:

System.Data.Objects

Assembly:

System.Data.Entity.dll

Initializes a new instance of the ObjectParameter class.

Overloads

ObjectParameter(String, Object)	Initializes a new instance of the ObjectParameter class with the specified name and value.
ObjectParameter(String, Type)	Initializes a new instance of the ObjectParameter class with the specified name and type.

ObjectParameter(String, Object)

Initializes a new instance of the ObjectParameter class with the specified name and value.

public:
 ObjectParameter(System::String ^ name, System::Object ^ value);

public ObjectParameter (string name, object value);

new System.Data.Objects.ObjectParameter : string * obj -> System.Data.Objects.ObjectParameter

Public Sub New (name As String, value As Object)

Parameters

name

String

The parameter name. This name should not include the "@" parameter marker that is used in Entity SQL statements, only the actual name. The first character of the expression must be a letter. Any successive characters in the expression must be either letters, numbers, or an underscore (_) character.

value

Object

The initial value (and inherently, the type) of the parameter.

Exceptions

ArgumentNullException

If the value of either argument is null.

ArgumentOutOfRangeException

If the value of the name argument is not valid. Parameter names must start with a letter and can only contain letters, numbers, and underscores.

Examples

This example adds new parameters to the collection. It iterates through the ObjectParameterCollection and displays the name, the type and the value of each parameter in the collection.

using (AdventureWorksEntities context =
    new AdventureWorksEntities())
{
    string queryString =
        @"SELECT VALUE contact FROM AdventureWorksEntities.Contacts
        AS contact WHERE contact.LastName = @ln
        AND contact.FirstName = @fn";

    ObjectQuery<Contact> contactQuery =
        new ObjectQuery<Contact>(queryString, context);

    // Add parameters to the collection.
    contactQuery.Parameters.Add(new ObjectParameter("ln", "Adams"));
    contactQuery.Parameters.Add(new ObjectParameter("fn", "Frances"));

    ObjectParameterCollection objectParameterCollection =
        contactQuery.Parameters;

    // Iterate through the ObjectParameterCollection.
    foreach (ObjectParameter result in objectParameterCollection)
    {
        Console.WriteLine("{0} {1} {2}", result.Name,
            result.Value,
            result.ParameterType);
    }
}

Remarks

This constructor creates a parameter from the specified name and value. The type of the parameter is inferred from the value.

When added to the ObjectParameterCollection, the parameter name cannot be changed. The parameter value can be changed through the Value property. After the query has been compiled, the value cannot be changed. For more information, see Query Builder Methods.

See also

• Querying Data as Objects and Shaping Results (Entity Framework)

ObjectParameter(String, Type)

Initializes a new instance of the ObjectParameter class with the specified name and type.

public:
 ObjectParameter(System::String ^ name, Type ^ type);

public ObjectParameter (string name, Type type);

new System.Data.Objects.ObjectParameter : string * Type -> System.Data.Objects.ObjectParameter

Public Sub New (name As String, type As Type)

Parameters

name

String

The parameter name. This name should not include the "@" parameter marker that is used in the Entity SQL statements, only the actual name. The first character of the expression must be a letter. Any successive characters in the expression must be either letters, numbers, or an underscore (_) character.

type

Type

The common language runtime (CLR) type of the parameter.

Exceptions

ArgumentNullException

If the value of either argument is null.

ArgumentOutOfRangeException

If the value of the name argument is invalid. Parameter names must start with a letter and can only contain letters, numbers, and underscores.

Remarks

When instantiated, the parameter name cannot be changed. The parameter value can be set or changed through the Value property. After the query has been compiled, the value cannot be changed. For more information, see Query Builder Methods.