Item Element (MSBuild)

Article
04/28/2015

Contains a user-defined item and its metadata. Every item that is used in a MSBuild project must be specified as a child of an ItemGroup element.

<Item Include="*.cs"
        Exclude="MyFile.cs"
        Remove="RemoveFile.cs"
        Condition="'String A'=='String B'" >
    <ItemMetadata1>...</ItemMetadata1>
    <ItemMetadata2>...</ItemMetadata2>
</Item>

Attributes and Elements

The following sections describe attributes, child elements, and parent elements.

Attributes

Attribute	Description
Include	Required attribute. The file or wildcard to include in the list of items.
Exclude	Optional attribute. The file or wildcard to exclude from the list of items.
Condition	Optional attribute. The condition to be evaluated. For more information, see MSBuild Conditions.
Remove	Optional attribute. The file or wildcard to remove from the list of items. This attribute is valid only if it's specified for an item in an ItemGroup that's in a Target.
KeepMetadata	Optional attribute. The metadata for the source items to add to the target items. Only the metadata whose names are specified in the semicolon-delimited list are transferred from a source item to a target item. For more information, see MSBuild Items. This attribute is valid only if it's specified for an item in an ItemGroup that's in a Target.
RemoveMetadata	Optional attribute. The metadata for the source items to not transfer to the target items. All metadata is transferred from a source item to a target item except metadata whose names are contained in the semicolon-delimited list of names. For more information, see MSBuild Items. This attribute is valid only if it's specified for an item in an ItemGroup that's in a Target.
KeepDuplicates	Optional attribute. Specifies whether an item should be added to the target group if it's an exact duplicate of an existing item. If the source and target item have the same Include value but different metadata, the item is added even if KeepDuplicates is set to false. For more information, see MSBuild Items. This attribute is valid only if it's specified for an item in an ItemGroup that's in a Target.

Child Elements

Element	Description
ItemMetadata	A user-defined item metadata key, which contains the item metadata value. There may be zero or more ItemMetadata elements in an item.

Parent Elements

Element	Description
ItemGroup	Grouping element for items.

Remarks

Item elements define inputs into the build system, and are grouped into item collections based on their user-defined collection names. These item collections can be used as parameters for tasks, which use the individual items in the collections to perform the steps of the build process. For more information, see MSBuild Items.

Using the notation @(myType) enables a collection of items of type myType to be expanded into a semicolon-delimited list of strings, and passed to a parameter. If the parameter is of type string, then the value of the parameter is the list of elements, separated by semicolons. If the parameter is an array of strings (string[]), then each element is inserted into the array based on the location of the semicolons. If the task parameter is of type ITaskItem[], then the value is the contents of the item collection together with any metadata attached. To delimit each item by using a character other than a semicolon, use the syntax @(myType, 'separator').

The MSBuild engine can evaluate wildcards such as * and ? and recursive wildcards such as /**/*.cs. For more information, see MSBuild Items.

Example

The following code example shows how to declare two items of type CSFile. The second declared item contains metadata that has MyMetadata set to HelloWorld.

<ItemGroup>
    <CSFile Include="engine.cs; form.cs" />
    <CSFile Include="main.cs" >
        <MyMetadata>HelloWorld</MyMetadata>
    </CSFile>
</ItemGroup>

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