How to add project level Preprocessor Definitions to a C# project

Using GUI

1. Open the project in Visual Studio
2. Right-Click on the project file in the solution explorer go to properties
3. Go to Build tab and Make sure you select the All Configurations in the configuration drop down
4. Make sure selected the All Platforms in Platform drop-down
5. Type the Preprocessor Definitions you want in the Conditional Compilation Symbols text box separated by semicolon

Directly in to Project file

1. Open the project file in a Text Editor 
2. Copy and paste this code to end of existing PropertyGroup
    <PropertyGroup Condition="'$(VariableName)'=='VarableValue'"> <DefineConstants>PDEF1;PDEF2;PDEF3</DefineConstants> </PropertyGroup>

3. If you not required to add a condition, delete the Condition="'$(VariableName)'=='VarableValue'" part
4. Save the project file and open from Visual Studio