C＃:使用ComboBox选择时语句错误

Question

从ComboBox选择'珠宝'时，" txt_qty＆amp; label6"是观看形式的，但是当选择GEM时，" TextBox5＆amp; label18"的观看方式不观看。请帮助

 private void combo_main_type_SelectedIndexChanged(object sender, EventArgs e)
    {
        if ((string)combo_main_type.SelectedItem == "Jewelry")
        {
            txt_qty.Visible = true;
            label6.Visible = true;
            txt_qty.Location = new System.Drawing.Point(213, 343);
            label6.Location = new System.Drawing.Point(40, 348);
        }
        else if ((string)combo_main_type.SelectedItem == "")
        {
            txt_qty.Visible = false;
            label6.Visible = false;
        }
        else if ((string)combo_main_type.SelectedItem == "Gem")
        {
            textBox5.Visible = true;
            label18.Visible = true;
            textBox5.Location = new System.Drawing.Point(213, 343);
            label18.Location = new System.Drawing.Point(40, 348);
        }
        else
        {
            textBox5.Visible = false;
            label18.Visible = false;
        }

    }

Answer 1

您需要做的是关注。

private void combo_main_type_SelectedIndexChanged(object sender, EventArgs e)
{
    if ((string)combo_main_type.SelectedItem == "Jewelry")
    {
        txt_qty.Visible = true;
        label6.Visible = true;
        txt_qty.Location = new System.Drawing.Point(213, 343);
        label6.Location = new System.Drawing.Point(40, 348);
        textBox5.Visible = false;
        label18.Visible = false;
    }
    else if ((string)combo_main_type.SelectedItem == "Gem")
    {
        textBox5.Visible = true;
        label18.Visible = true;
        textBox5.Location = new System.Drawing.Point(213, 343);
        label18.Location = new System.Drawing.Point(40, 348);
        txt_qty.Visible = false;
        label6.Visible = false;
    }
    else
    {
        textBox5.Visible = false;
        label18.Visible = false;
        txt_qty.Visible = false;
        label6.Visible = false;
    }
}