Why Are My List Items Overwritten When Adding Multiple Objects?

List Value Overwrites During Multiple Item Additions

Issue:

Adding multiple items to a list results in all list items being overwritten with the value of the last added item. This happens regardless of the items' initial values.

Causes:

• Reference-Based Assignment: In object-oriented contexts, passing objects by reference means any property modifications affect the original object.
• Object Reuse: The code likely reuses a single object instance within a loop. Subsequent assignments overwrite the object's properties, leading to the observed overwrite behavior.

Resolution:

The solution involves creating a new object instance for each iteration:

<code class="language-csharp">foreach (string t in tagList)
{
    Tag _tag = new Tag(); // New Tag object for each iteration

    _tag.tagName = t;
    tags.Add(_tag);
}</code>

Alternative: Utilizing Structs

Switching from a class to a struct eliminates the overwrite problem because:

• Value-Based Passing: Structs are value types; they're passed by value.
• Object Copying: When a struct is passed, a copy is created, not a reference. Each Add operation creates a new struct instance, maintaining unique values.

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