Creating a System.Windows.Forms.ListBox object: choose all correct syntaxes.

Difficulty: Easy

using System.Windows.Forms; ListBox lb = new ListBox();
using LBControl = System.Windows.Forms; LBControl lb = new LBControl();
System.Windows.Forms.ListBox lb = new System.Windows.Forms.ListBox();
using LBControl lb = new System.Windows.Forms.ListBox;
using LBControl = System.Windows.Forms.ListBox; LBControl lb = new LBControl();

Correct Answer: using System.Windows.Forms; ListBox lb = new ListBox();

Explanation:

Introduction / Context:
This question verifies your understanding of using directives, type aliases, and fully qualified names for instantiating Windows Forms controls.

Given Data / Assumptions:

ListBox is in the System.Windows.Forms namespace.
We can either import the namespace, fully qualify the type, or alias the type.

Concept / Approach:
There are three valid approaches: (1) import the namespace and use the type name; (2) fully qualify the type; (3) alias the specific type and instantiate via the alias. Aliasing a namespace to create an instance directly is incorrect.

Step-by-Step Solution:

Option A: Valid—namespace imported; type used directly.Option C: Valid—fully qualified type used twice (declaration and instantiation).Option E: Valid—type alias declared for System.Windows.Forms.ListBox, then instantiated.Options B and D: Invalid—B aliases a namespace, then tries to instantiate it; D misuses using in an object creation context.

Verification / Alternative check:
Compile each option in a minimal project; A, C, and E succeed; B and D fail.

Why Other Options Are Wrong:
Namespaces are containers, not constructible types; also 'using' cannot be used directly in a variable declaration like D.

Common Pitfalls:
Aliasing namespaces instead of types and assuming they can be constructed.

Final Answer:
using System.Windows.Forms; ListBox lb = new ListBox(); (Also valid in context: fully qualified type or type alias patterns.)

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Creating a System.Windows.Forms.ListBox object: choose all correct syntaxes.

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