how is MS Build properties hierarchy maintained? - msbuild

Question

Can anyone tell me how does the MsBuild picks up the value of the property..??
eg.
<TempProperty>Property Value</TempProperty>
now I can use $(TempProperty) anywhere to get the value of it.
now the scenario is I have made custom task that has configuration like this..
<PropertyGroup>
<ItemList>
<ConfigChange>
<PlaceHolder>#MACHINE_NAME#</PlaceHolder>
<Value>$(TempProperty)</Value>
<IsList>False</IsList>
</ConfigChange>
</ItemList>
</PropertyGroup>
now instead of getting "Property Value" in the tag I am getting $(TempProperty)... can anyone tell me how to get actual value in tag ???
thanks in advance.
Hey, Guys I have got the actual Problem and solution too... I think I was not able to describe my problem here.. .the problem was.. In my custom task I was passing the file path of the file containing the above ItemList tag..now when I tried to parse the XMLNode "ItemList" it was getting "$(TempProperty)" as value in the Item.. and I think thats correct because thats what is present in the passed XML.
So to overcome the issue , I did two things..
I created ItemGroup instead of propertyGroup and passed that ItemGroup to my custom task instead of file path.. thus now at my code I am getting the desired values.
thanks for your replies.

Answer 1

There's not enough there to really diagnose your problem. It looks correct at first glance, but where is the PropertyGroup for TempProperty declared?
For an illustrative example, here's a snippet from a C# project file:
<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="4.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
<PropertyGroup>
<Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
...
</PropertyGroup>
<PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
...
</PropertyGroup>
The Configuration Property is being set to Debug (if it is blank at at that point). In the following group, it keys off of the Confuration and Platform properties.
The only gotcha tidbit is that for a property value to show up properly, it must be declared before it is used.
Please try to provide a little more context, that may help with understanding the issue.

Answer 2

I just tried this:
<Project
xmlns="http://schemas.microsoft.com/developer/msbuild/2003"
ToolsVersion="4.0"
DefaultTargets="Demo" >
<PropertyGroup>
<TempProperty>property value</TempProperty>
<ItemList>
<ConfigChange>
<PlaceHolder>#MACHINE_NAME#</PlaceHolder>
<Value>$(TempProperty)</Value>
<IsList>False</IsList>
</ConfigChange>
</ItemList>
</PropertyGroup>
<Target Name="Demo">
<Message Text="TempProperty: $(TempProperty)"/>
<Message Text="ItemList: $(ItemList)"/>
</Target>
</Project>
And my results where:
Task "Message"
TempProperty: property value
Done executing task "Message".
Task "Message"
ItemList:
<ConfigChange xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
<PlaceHolder>#MACHINE_NAME#</PlaceHolder>
<Value>property value</Value>
<IsList>False</IsList>
</ConfigChange>
Done executing task "Message".
Are you seeing something else?

Answer 3

on Ritch's suggestion I am adding my solution.
Initially I had
<TempProperty>Property Value</TempProperty>
<PropertyGroup>
<ItemList>
<ConfigChange>
<PlaceHolder>#MACHINE_NAME#</PlaceHolder>
<Value>$(TempProperty)</Value>
<IsList>False</IsList>
</ConfigChange>
</ItemList>
</PropertyGroup>
now my problem was I was providing my properties file part to my custom task
like
<UpdatePegasusConfigXML
Environment="$(Environment)"
Instance="$(Instance)"
BuildSourceRoot="$(BuildSourceRoot)"
></UpdatePegasusConfigXML>
now since I was providing file path itself so it took the value which was put in "Value" tag and was not picking up the property value, thus at code level I was getting "$(TempProperty)" instead of "Property Value"
now what I did was instead of creating property Group I created ItemGroup like this
<ItemGroup>
<PlaceHolders Include="#MACHINE_NAME#">
<Value>$(TempProperty)</Value>
<IsList>True</IsList>
</PlaceHolders>
</ItemGroup>
now I updated my custom task to take IteamGroup as one of the inputs, thus calling changed to
<UpdatePegasusConfigXML
Environment="$(Environment)"
Instance="$(Instance)"
BuildSourceRoot="$(BuildSourceRoot)"
PlaceHolders="#(PlaceHolders)"
></UpdatePegasusConfigXML>
now at code level I am able to get the value in "Value" tag of the ItemGroup.
I hope I had explained my solution that it was understandable.