Why Does `ExecuteNonQuery()` Fail with an 'Uninitialized Connection Property' Error?

ExecuteNonQuery: Failure Due to Uninitialized Connection Property

Question:

When attempting to execute an SQL command using ExecuteNonQuery(), an error is encountered indicating that the connection property has not been initialized. What could be causing this issue?

Answer:

The error message, "ExecuteNonQuery: Connection property has not been initialized," suggests that the SqlConnection object has not been properly assigned to the SqlCommand object. To resolve this issue, the connection property of the SqlCommand must be explicitly set.

Solution:

One method to assign the connection is through the constructor of the SqlCommand class:

cmd.InsertCommand = new SqlCommand("INSERT INTO Application VALUES (@EventLog, @TimeGenerated, @EventType, @SourceName, @ComputerName, @InstanceId, @Message) ", connection1);

Alternatively, the connection property can be assigned directly:

cmd.InsertCommand.Connection = connection1;

Additional Considerations:

• Using Statement: It is recommended to use the using statement for objects implementing IDisposable, such as SqlConnection, to ensure proper resource cleanup and connection closure.
• Connection Pooling: Creating and closing connections repeatedly (e.g., for each entry in the foreach loop) is an unnecessary overhead. Instead, consider creating and opening the connection once outside the loop and closing it only after the loop has completed.

Sample Code:

using (var connection1 = new SqlConnection(@"Data Source=.\sqlexpress;Initial Catalog=syslog2;Integrated Security=True"))
using (var cmd = new SqlDataAdapter())
using (var insertCommand = new SqlCommand("INSERT INTO Application VALUES (@EventLog, @TimeGenerated, @EventType, @SourceName, @ComputerName, @InstanceId, @Message) "))
{
    insertCommand.Connection = connection1;
    cmd.InsertCommand = insertCommand;

    // Other code...

    connection1.Open();
    insertCommand.ExecuteNonQuery();
}

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