• Article

VariableDispenser Class

Accesses the Variables collection during package execution. This class cannot be inherited.

Inheritance Hierarchy

System.Object
  Microsoft.SqlServer.Dts.Runtime.DtsObject
    Microsoft.SqlServer.Dts.Runtime.VariableDispenser

Namespace:  Microsoft.SqlServer.Dts.Runtime
Assembly:  Microsoft.SqlServer.ManagedDTS (in Microsoft.SqlServer.ManagedDTS.dll)

Syntax

'Declaration
Public NotInheritable Class VariableDispenser _
    Inherits DtsObject
'Usage
Dim instance As VariableDispenser

public sealed class VariableDispenser : DtsObject

public ref class VariableDispenser sealed : public DtsObject

[<SealedAttribute>]
type VariableDispenser =  
    class
        inherit DtsObject
    end

public final class VariableDispenser extends DtsObject

The VariableDispenser type exposes the following members.

Methods

  Name Description
Public method Contains Specifies whether an item can be retrieved from the VariableDispenser collection by using indexing without throwing an exception.
Public method Equals Determines whether two object instances are equal. (Inherited from DtsObject.)
Protected method Finalize (Inherited from Object.)
Public method GetHashCode Returns the hash code for this instance. (Inherited from DtsObject.)
Public method GetQualifiedName Returns the qualified name of the variable.
Public method GetType (Inherited from Object.)
Public method GetVariables Locks the variables that are in the read-only list and the read/write list.
Public method LockForRead Adds the variable to the list of variables to be locked for read-only access.
Public method LockForWrite Adds the variable to the list of variables to be locked for read/write access.
Public method LockOneForRead Puts the variable in a list, and then locks it for read-only access.
Public method LockOneForWrite Puts the variable in a list, and then locks it for read/write access.
Protected method MemberwiseClone (Inherited from Object.)
Public method Reset Clears both the read-only list and read/write list when the call to GetVariables fails.
Public method ToString (Inherited from Object.)

Top

Remarks

There are two scenarios for using the variable dispenser.

  1. You want just one variable. In this scenario, call LockOneForRead or LockOneForWrite, and a collection with one element is returned.

  2. You want several variables. In this scenario, call LockForRead and LockForWrite several times, one for each variable. This builds up two lists, one list that contains variables for reading and one list that contains variables for writing. Next, call GetVariables, which gives you a collection that contains all of the locked variables. If GetVariables succeeds, the two lists, which are the lists of variable names, not actual locks, are cleared.

To explicitly release the locks, call Unlock on the collection. This method unlocks the variables themselves. If GetVariables fails, the lists remain unchanged, and you can call GetVariables again. If you still do not succeed in obtaining the variables, call Reset to clear the lists and bring the variable dispenser back to its initial state.

The Variables collection contains a Locked property that indicates whether a variable dispenser collection of variables is locked (true) or unlocked (false). The reason to review this property is that some tasks explicitly release locks to the variables they are using, and calling Unlock twice throws an error. Therefore, you should use this property to determine whether the dispensed collection is locked before calling Unlock.

Important

The VariableDispenser is used with the Runtime classes. If you are using data flow components (Microsoft.SqlServer.Dts.Pipeline), then you may be required to use the IDTSVariableDispenser100 instead. To know which variable dispenser to use, see the documentation for the object you are acquiring variables on, and verify the return object of the method.

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.