Unit Test Error

Question

Sir, I need your help in the following topic:-

when i test my ADO.NET form using unit test, i got an error:-

public void button2_ClickTest()
        {
            Form1_Accessor target = new Form1_Accessor(); // TODO: Initialize to an appropriate value
            object sender = null; // TODO: Initialize to an appropriate value
            EventArgs e = null; // TODO: Initialize to an appropriate value
            target.button2_Click(sender, e);
            Assert.Inconclusive("A method that does not return a value cannot be verified.");
        }


errror in target.button2_Click(sender, e); line 

how the error came and how can it solved?

please help me in this topic.