Item Element (MSBuild) 

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

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

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

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 contained in the collection to perform the steps of the build process. For more infomration, see MSBuild Items.

Using the notation @(myType) allows 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[]), each element is inserted into the array based on the location of the semicolons. If the task parameter is of type ITaskItem[], the value is the contents of the item collection with any metadata attached. To delimit each item with a character other than a semicolon, use the syntax @(myType, 'separator').

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

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

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

MSBuild Items
MSBuild Properties
MSBuild Project File Schema Reference