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ColumnAttribute.Expression Property

.NET Framework 4

Other Versions

Gets or sets whether a column is a computed column in a database.

Namespace: System.Data.Linq.Mapping
Assembly: System.Data.Linq (in System.Data.Linq.dll)

Syntax

C++

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public string Expression { get; set; }

Property Value

Type: System.String
Default = empty.

Remarks

Use this property when you use CreateDatabase to define a column as containing computed values.

For example, if you want to create a column defined in SQL as InventoryVal AS UnitPrice * UnitsInStock, use the following expression string: "UnitPrice * UnitsInStock".

Note
LINQ to SQL does not support computed columns as primary keys.

Examples

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	[Column(Storage="_UnitPrice", DbType="Money",Expression="UnitPrice + 1.00")]
	public System.Nullable<decimal> UnitPrice
	{
		get
		{
			return this._UnitPrice;
		}
		set
		{
			if ((this._UnitPrice != value))
			{
				this.OnUnitPriceChanging(value);
				this.SendPropertyChanging();
				this._UnitPrice = value;
				this.SendPropertyChanged("UnitPrice");
				this.OnUnitPriceChanged();
			}
		}
	}

Version Information

.NET Framework

Supported in: 4, 3.5

.NET Framework Client Profile

Supported in: 4

Platforms

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Reference

ColumnAttribute Class

System.Data.Linq.Mapping Namespace

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