DataParameter Class

Article
02/23/2011

Represents a data parameter that is derived from a data source command, or that is passed with a command to a data source.

Inheritance Hierarchy

System.Object
Microsoft.VisualStudio.Data.Framework.DataParameter
Microsoft.VisualStudio.Data.Framework.AdoDotNet.AdoDotNetParameter

Namespace: Microsoft.VisualStudio.Data.Framework
Assembly: Microsoft.VisualStudio.Data.Framework (in Microsoft.VisualStudio.Data.Framework.dll)

Syntax

'Declaration
Public MustInherit Class DataParameter _
    Implements IVsDataParameter, IVsDataParameterDescriptor

public abstract class DataParameter : IVsDataParameter, 
    IVsDataParameterDescriptor

public ref class DataParameter abstract : IVsDataParameter, 
    IVsDataParameterDescriptor

[<AbstractClass>]
type DataParameter =  
    class
        interface IVsDataParameter
        interface IVsDataParameterDescriptor
    end

public abstract class DataParameter implements IVsDataParameter, IVsDataParameterDescriptor

The DataParameter type exposes the following members.

Constructors

	Name	Description
	DataParameter()	Initializes a new instance of the DataParameter class.
	DataParameter(Boolean)	Initializes a new instance of the DataParameter class, specifying whether the instance was derived using the DeriveParameters method.

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Properties

	Name	Description
	DefaultSize	Gets an integer value specifying the default size for the current parameter type.
	Descriptor	Gets information that describes the data parameter.
	Direction	Gets or sets a DataParameterDirection object specifying the direction of the parameter.
	HasDescriptor	Gets a value indicating whether the data parameter exposes its IVsDataParameterDescriptor implementation through the Descriptor property.
	IsDerived	Gets a Boolean value that indicates whether the current parameter was derived from the data source.
	IsFixedSize	Gets a Boolean value indicating whether the size for the current parameter type is fixed.
	IsNullable	Gets a Boolean value indicating whether the current parameter can have a null value provided that it is derived.
	IsOptional	Gets a Boolean value indicating whether the current parameter is optional, provided that it is derived.
	Name	Gets or sets the string literal name of the current parameter.
	Size	Gets or sets an integer value specifying the size of the parameter.
	Type	Gets or sets the data source–specific type of the parameter.
	Value	Gets or sets the value of the parameter.

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Methods

	Name	Description
	Equals	Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
	Finalize	Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
	GetDirectionCore	Retrieves the parameter direction.
	GetHashCode	Serves as a hash function for a particular type. (Inherited from Object.)
	GetIsNullableCore	Retrieves a Boolean value indicating whether the current parameter can be nulla null reference (Nothing in Visual Basic).
	GetIsOptionalCore	Retrieves a Boolean value indicating whether the parameter is optional.
	GetNameCore	Retrieves the name of the parameter.
	GetSizeCore	Retrieves an integer value specifying the size of the parameter.
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	GetTypeCore	Retrieves the data source–specific type of the parameter.
	GetTypeFrom	Infers the data source–specific parameter type from a parameter value.
	GetValueCore	Retrieves the value of a specified parameter.
	IsSupportedDirection	Retrieves a Boolean value indicating whether the specified parameter direction is supported.
	IsValidType	Retrieves a Boolean value indicating whether the specified data source–specific type is a valid type.
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	OnDirectionChanged	Called when the Direction property is changed to signal a change in the parameter direction.
	OnDirectionChanging	Called when the Direction property is about to change.
	OnNameChanged	Called when the Name property has changed.
	OnNameChanging	Called when the Name property is about to change.
	OnSizeChanged	Called when the Size property has changed.
	OnSizeChanging	Called when the Size property is about to change.
	OnTypeChanged	Called when the Type property has changed.
	OnTypeChanging	Called when the Type property is about to change.
	OnValueChanged	Called when the Value property has changed.
	OnValueChanging	Called when the Value property is about to change.
	Parse	Disassembles a parameter value in a string format and converts the value to the correct type.
	SetDirectionCore	Sets the direction of the parameter by using the DataParameterDirection enumeration.
	SetNameCore	Sets the name of the parameter.
	SetSizeCore	Sets an integer value specifying the size of the current parameter.
	SetTypeCore	Sets the data type of the current parameter.
	SetValueCore	Sets the value of the parameter.
	ToString	Retrieves a string representation of the value of the current parameter. (Overrides Object.ToString().)
	TryConvertValue	Attempts to convert the specified value to the specified type.

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Fields

	Name	Description
	NullSize	A public size constant holding the value of zero.

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Remarks

This class uses an indirect mechanism for implementing parameter properties. Each property get method calls a virtual protected method that retrieves the property. Each property set method, however, calls three virtual protected methods: one indicating that the property is changing, another actually changing the property, and a third indicating that the property has changed.

This allows the property setter to isolate the handling of invalid input in the property changing method, set the property, and apply any side effects in the property changed method. This also allows the base class to provide some default error checking to match the semantics defined by the parameter interface.

Thread Safety

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

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