IDataParameter Interface

Definition

Namespace:

System.Data

Assembly:

System.Data.Common.dll

Represents a parameter to a Command object, and optionally, its mapping to DataSet columns; and is implemented by .NET data providers that access data sources.

public interface class IDataParameter

public interface IDataParameter

type IDataParameter = interface

Public Interface IDataParameter

Derived

System.Data.Common.DbParameter

System.Data.EntityClient.EntityParameter

System.Data.IDbDataParameter

System.Data.Odbc.OdbcParameter

System.Data.OleDb.OleDbParameter

System.Data.OracleClient.OracleParameter

Examples

The following example creates multiple instances of the derived class, SqlParameter, through the SqlParameterCollection collection within the SqlDataAdapter. These parameters are used to select data from the data source and place the data in the DataSet. This example assumes that a DataSet and a SqlDataAdapter have already been created with the appropriate schema, commands, and connection.

public void AddSqlParameters()
{
// ...
// create categoriesDataSet and categoriesAdapter
// ...

  categoriesAdapter.SelectCommand.Parameters.Add(
    "@CategoryName", SqlDbType.VarChar, 80).Value = "toasters";
  categoriesAdapter.SelectCommand.Parameters.Add(
    "@SerialNum", SqlDbType.Int).Value = 239;
  categoriesAdapter.Fill(categoriesDataSet);
}

Public Sub AddSqlParameters()
    ' ...
    ' create categoriesDataSet and categoriesAdapter
    ' ...
    categoriesAdapter.SelectCommand.Parameters.Add( _
        "@CategoryName", SqlDbType.VarChar, 80).Value = "toasters"
    categoriesAdapter.SelectCommand.Parameters.Add( _
        "@SerialNum", SqlDbType.Int).Value = 239
    
    categoriesAdapter.Fill(categoriesDataSet)
End Sub

Remarks

The IDataParameter interface allows an inheriting class to implement a Parameter class, which represents a parameter to a Command object. For more information about Parameter classes, see Configuring Parameters and Parameter Data Types.

An application does not create an instance of the IDataParameter interface directly, but creates an instance of a class that inherits IDataParameter.

Classes that inherit IDataParameter must implement the inherited members, and typically define additional members to add provider-specific functionality. For example, the IDataParameter interface defines the DbType property. In turn, the OleDbParameter class inherits this property, and also defines the OleDbType property.

Notes to Implementers

To promote consistency among .NET Framework data providers, name the inheriting class in the form Prv Parameter where Prv is the uniform prefix given to all classes in a specific .NET Framework data provider namespace. For example, Sql is the prefix of the SqlCommand class in the System.Data.SqlClient namespace.

When you inherit from the IDataParameter interface, you should implement the following constructors:

Item	Description
PrvParameter()	Initializes a new instance of the Parameter class.
PrvParameter(string name, PrvDbType dataType)	Initializes a new instance of the Parameter class with the parameter name and data type.
PrvParameter(string name, object value)	Initializes a new instance of the Parameter class with the parameter name and an object that is the value of the Parameter.
PrvParameter(string name, PrvDbType dataType, int size)	Initializes a new instance of the Parameter class with the parameter name, data type, and width.
PrvParameter(string name, PrvDbType dataType, int size, string srcColumn)	Initializes a new instance of the DbParameter class with the parameter name, data type, width, and source column name.
PrvParameter(string parameterName, PrvDbType dbType, int size, ParameterDirection direction, Boolean isNullable, Byte precision, Byte scale, string srcColumn, DataRowVersion srcVersion, object value)	Initializes a new instance of the OleDbParameter class with the parameter name, data type, width, source column name, parameter direction, numeric precision, and other properties.

Properties

DbType	Gets or sets the DbType of the parameter.
Direction	Gets or sets a value indicating whether the parameter is input-only, output-only, bidirectional, or a stored procedure return value parameter.
IsNullable	Gets a value indicating whether the parameter accepts null values.
ParameterName	Gets or sets the name of the IDataParameter.
SourceColumn	Gets or sets the name of the source column that is mapped to the DataSet and used for loading or returning the Value.
SourceVersion	Gets or sets the DataRowVersion to use when loading Value.
Value	Gets or sets the value of the parameter.