Object cannot be cast from DBNull to other types.

Question

Good day, I want to check my DB connection and here's my code.

private void Button2_Click(object sender, EventArgs e)
        {
            
            
            string mysqlcon = "SERVER=192.XXX.XXX.XXX;PORT=XXXX;DATABASE=XXXX;UID=XXXX;PASSWORD=XXXX;";
            MySqlConnection mysqlconnection = new MySqlConnection(mysqlcon);
            try
            {
                mysqlconnection.Open();
                label2.ForeColor = System.Drawing.Color.Green;
                label2.Text = "Connected";
            }
            catch (Exception ex)
            {
                label2.ForeColor = System.Drawing.Color.Red;
                label2.Text = ex.Message;
            }
            finally
            {
                mysqlconnection.Close();
            }
        }

now, when I click one's the CHECK button it shows like this.

It show's the error message that say. "Object cannot be cast from DBNull to other types."

Now, when I click the check button twice, it shows like this.

It's shown Connected. I don't know why.

Please help me to fix this problem. Thank you so much.

Answer 1

This error shouldn't have happened when you have a connection with your SQL server.

It's something to do with the "Data Insert", which means you've inserted an Null value into a non-value field.

So plz make sure you haven't pressed the "Insert" button with an empty textbox.

The solution is:

1, Click the "CHECK" first.

2, Write something into the TextBox.

3, Click "Insert".