Question

Please, what is wrong with this:

private void Form2_Load(object sender, EventArgs e)
{
    switch (Form2.Tag) //error
    {
        case "desc":
            MessageBox.Show("desc");
        break;

        case "sms":
            MessageBox.Show("sms");
        break;
    }
}

Error:

An object reference is required for the non-static field, method, or property System.Windows.Forms.Control.Tag.get

Answer 1

You probably meant to say this.Tag. Referencing the Tag property will require an instance of Form2, hence the error message you received.

Edit:

Forgot Tag was an object. Cast it to a string and your statement should work:

switch ((string)this.Tag)