The yield
contextual keyword actually does quite a lot here.
The function returns an object that implements the IEnumerable<object>
interface. If a calling function starts foreach
ing over this object, the function is called again until it "yields". This is syntactic sugar introduced in C# 2.0. In earlier versions you had to create your own IEnumerable
and IEnumerator
objects to do stuff like this.
The easiest way understand code like this is to type-in an example, set some breakpoints and see what happens. Try stepping through this example:
public void Consumer()
{
foreach(int i in Integers())
{
Console.WriteLine(i.ToString());
}
}
public IEnumerable<int> Integers()
{
yield return 1;
yield return 2;
yield return 4;
yield return 8;
yield return 16;
yield return 16777216;
}
When you step through the example, you'll find the first call to Integers()
returns 1
. The second call returns 2
and the line yield return 1
is not executed again.
Here is a real-life example:
public IEnumerable<T> Read<T>(string sql, Func<IDataReader, T> make, params object[] parms)
{
using (var connection = CreateConnection())
{
using (var command = CreateCommand(CommandType.Text, sql, connection, parms))
{
command.CommandTimeout = dataBaseSettings.ReadCommandTimeout;
using (var reader = command.ExecuteReader())
{
while (reader.Read())
{
yield return make(reader);
}
}
}
}
}
AssemblyVersion
Where other assemblies that reference your assembly will look. If this number changes, other assemblies have to update their references to your assembly! Only update this version, if it breaks backward compatibility. The AssemblyVersion
is required.
I use the format: major.minor. This would result in:
[assembly: AssemblyVersion("1.0")]
If you're following SemVer strictly then this means you only update when the major changes, so 1.0, 2.0, 3.0, etc.
AssemblyFileVersion
Used for deployment. You can increase this number for every deployment. It is used by setup programs. Use it to mark assemblies that have the same AssemblyVersion
, but are generated from different builds.
In Windows, it can be viewed in the file properties.
The AssemblyFileVersion is optional. If not given, the AssemblyVersion is used.
I use the format: major.minor.patch.build, where I follow SemVer for the first three parts and use the buildnumber of the buildserver for the last part (0 for local build).
This would result in:
[assembly: AssemblyFileVersion("1.3.2.254")]
Be aware that System.Version names these parts as major.minor.build.revision
!
AssemblyInformationalVersion
The Product version of the assembly. This is the version you would use when talking to customers or for display on your website. This version can be a string, like '1.0 Release Candidate'.
The AssemblyInformationalVersion
is optional. If not given, the AssemblyFileVersion is used.
I use the format: major.minor[.patch] [revision as string]. This would result in:
[assembly: AssemblyInformationalVersion("1.0 RC1")]
Best Answer
Allows me to replace:
With: