How to paste text in textbox current cursor?

This ensures that the cursor is at some position within the textbox, then inserts the text wherever the cursor is located.

        if (textBox1.CaretIndex <= 0)
        {

               textBox1.Focus();
     textBox1.Text = textBox1.Text.Insert(
                textBox1.CaretIndex, "Whatever");
        }
        else
        {
            textBox1.Text = textBox1.Text.Insert(
                textBox1.CaretIndex, "Whatever");
        }