Why Does My WinForms Listbox Show \'System.Data.DataRowView\' Instead of the Expected Values?

Unraveling the Mystery of "System.Data.DataRowView" in WinForms Listboxes

Encountering "System.Data.DataRowView" when expecting actual values in your WinForms Listbox can be perplexing. Here's an in-depth exploration of the culprit:

Your code interacts with a database, retrieves data using a MySQL data adapter and adapter, and assigns the data to a DataTable. The Listbox's DisplayMember is set to "NameAndScore," and the DataTable serves as the Listbox's data source.

The root cause lies in the type of data being assigned to the Listbox. When binding data to a Listbox, you typically specify either a string or an object as its DisplayMember. Each item in the Listbox is then created using the DisplayMember's value from the bound data.

In your code, the DisplayMember is "NameAndScore," which is a calculated column in your SQL query. This column combines two values, "Name" and "Score," with a space in between. The DataTable contains DataRow objects, and each row represents a record from the database. When the Listbox binds to the DataTable, it displays the values of the DisplayMember for each DataRow object.

Since each DataRow represents the entire row from the database, the value of the DisplayMember is not just a string but a DataRowView object. A DataRowView is a wrapper around a DataRow object, providing access to its values, relationships, and other properties.

To resolve this issue and display the actual "Name" and "Score" values:

1. Add a separate column to your SQL query for each of the values you want to display in the Listbox. For example:

<code class="sql">SELECT Name, Score, CONCAT(Name, ' ', Score) as NameAndScore
FROM highscore ORDER BY Score DESC</code>

2. Modify your code to set the Listbox's DisplayMember to the appropriate column name, such as "Name":

<code class="c#">lstNames.DisplayMember = "Name";</code>

By following these steps, you can ensure that your Listbox displays the desired values from your database. Remember, it's important to understand the data types involved when binding to a Listbox to avoid such discrepancies.

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