One option is to simply use the Collection type directly from C. This is a standard type in the Microsoft. Net language. The closest collection in the standard BCL though is Hashtable.
Converting between Hashtable and Collection should be fairly straight forward. Note: This is not a direct mapping though. The Collection type supports a number of operations which Hashtable does not like: before and after values, index by number or key, etc My approach would be to use one type consistently throughout the application and change either the C or VB project appropriately. Unless you can change the method, so that it takes ICollection , IEnumerable or their generic variants, you have to pass an instance of Microsoft.
Collection to that method. From the point of view of C , Microsoft. Collection is just a class and you can work with it as with any other class, i. There is no such thing as a "C object", or a "VisualBasic.
C devs often frown upon Microsoft. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow.
Next Statement. The For Each Next Statement calls GetEnumerator to obtain an enumerator object to support iteration over a collection's elements.
Normally, you use a For Each Next loop to traverse a collection or array, and you do not need to call GetEnumerator explicitly. If you need closer control over the iteration than the For Each Next statements provide, you can use the GetEnumerator method to perform a customized traversal.
The following are some cases in which you might need to do this. The following example instead uses the TryGetValue method quickly find an item by key.
LINQ queries provide filtering, ordering, and grouping capabilities. The LINQ query returns a different collection that contains the results. The following example illustrates a procedure for sorting a collection. Each call to the CompareTo method makes a single comparison that is used for sorting. User-written code in the CompareTo method returns a value for each comparison of the current object with another object.
The value returned is less than zero if the current object is less than the other object, greater than zero if the current object is greater than the other object, and zero if they are equal.
This enables you to define in code the criteria for greater than, less than, and equal. In the ListCars method, the cars. Sort statement sorts the list. For additional information, see Enumerating a Collection. Although you can define a custom collection, it is usually better to instead use the collections that are included in the.
The following example defines a custom collection class named AllColors. This class implements the IEnumerable interface, which requires that the GetEnumerator method be implemented.
The GetEnumerator method returns an instance of the ColorEnumerator class. ColorEnumerator implements the IEnumerator interface, which requires that the Current property, MoveNext method, and Reset method be implemented. An iterator is used to perform a custom iteration over a collection. An iterator can be a method or a get accessor. An iterator uses a Yield statement to return each element of the collection one at a time.
You call an iterator by using a For Each…Next statement. Each iteration of the For Each loop calls the iterator. When a Yield statement is reached in the iterator, an expression is returned, and the current location in code is retained.
Execution is restarted from that location the next time that the iterator is called. For more information, see Iterators Visual Basic. The following example uses an iterator method. The iterator method has a Yield statement that is inside a For…Next loop. In the ListEvenNumbers method, each iteration of the For Each statement body creates a call to the iterator method, which proceeds to the next Yield statement.
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