When using out parameters it can be often advantageous to declare them right inline with the out parameter declaration itself. This reduces the line count, allows var to be used to infer the type from the method signature and prevents use before initialization.

Additionally C# 7.0 allows out parameters to be used in constructor initializers, query clauses, field initializers and property initializers.

Code

Now

if (int.TryParse(txtQuantity.Value, out var quantity)) {
    order.Quantity = quantity;
}

Before

int quantity;
if (int.TryParse(txtQuantity.Value, out quantity)) {
    order.Quantity = quantity;
}

More information

• Out variables in C# 7.0 @ DotNetTutorials