ms Build engine find existing item or remove duplicate items - msbuild

Question

I am currently working on an application that generates C# code files and adds them to an existing project. To edit the project I'm using Microsoft.Build.BuildEngine, and loading the exisiting .csproj file into the Project class.
csproj = new Project(new Engine(),"3.5");
csproj.Load("/myproject.csproj");
After wich I am able to add refeneces and compile items as I need. However I do not know if the files or references are already in the .csproj file, so currently they get added multiple times, which I do not want.
for example:
<Reference Include="System" />
<Reference Include="System" />
<Reference Include="System.Core" />
<Reference Include="System.Core" />
Does anyone know of a way I can check if a builditem exists before I add it to the project? Or of a way to remove duplicated builditems after I've added them?

Answer 1

You could iterate through the EvaluatedItems of your Project Object
This sample code demonstrates how to check builditem existence before adding it :
// Create a new Engine object.
Engine engine = new Engine(Environment.CurrentDirectory);
// Create a new Project object.
Project csproj = new Project(new Engine(),"3.5");
csproj.Load("/myproject.csproj");
BuildItemGroup referenceItemGroup;
var currentReferences = new HashSet<string>();
// Iterate through each ItemGroup in the Project.
foreach (BuildItemGroup ig in csproj.ItemGroups)
{
// Iterate through each Item in the ItemGroup.
foreach (BuildItem item in ig)
{
if (item.Name == "Reference")
{
currentReferences.Add(item.Include);
referenceItemGroup = ig;
}
}
}
// Add only non existing reference
if (!currentReferences.Contains("NewReferenceToAdd"))
{
if (referenceItemGroup != null)
{
referenceItemGroup.AddNewItem("Reference", "IncludeValue");
}
}
And this one how to remove duplicates item
// Create a new Engine object.
Engine engine = new Engine(Environment.CurrentDirectory);
// Create a new Project object.
Project csproj = new Project(new Engine(),"3.5");
csproj.Load("/myproject.csproj");
var currentReferences = new HashSet<string>();
// Iterate through each ItemGroup in the Project.
foreach (BuildItemGroup ig in csproj.ItemGroups)
{
var itemsToRemove = new List<BuildItem>;
// Iterate through each Item in the ItemGroup.
foreach (BuildItem item in ig)
{
if (item.Name == "Reference")
{
if (currentReferences.Contains(item.Include))
{
itemsToRemove.Add(item);
}
else
{
currentReferences.Add(item.Include);
}
}
}
// Remove duplicate items
foreach (BuildItem itemToRemove in itemsToRemove)
{
ig.RemoveItem(itemToRemove);
}
}