MessageBox的Buttons和三級聯動

一、MessageBox的Buttons

 MessageBox.Show可以出現有按鈕的對話框

例如：

DialogResult dr = MessageBox.Show("是否要繼續嗎？", "警告！！！", MessageBoxButtons.OKCancel);//它彈出的對話框如下圖所示
if (dr == DialogResult.OK)//只有按下確定按鈕才執行下麵
{
label1.Text = "天氣不錯";
}

除此之外MessageBoxButtons還有好幾種對話框

二、三級聯動

三個Combobox

public Form1()// Form1的構造函數
{
InitializeComponent();

AreaDataBind(comboBox1, "0001");
AreaDataBind(comboBox2, comboBox1.SelectedValue.ToString());
AreaDataBind(comboBox3, comboBox2.SelectedValue.ToString());
}

public void AreaDataBind(ComboBox cb, string Pcode)
{
cb.DataSource = new ChinaData().Select(Pcode);//數據源
cb.DisplayMember = "AreaName";//顯示值
cb.ValueMember = "AreaCode";//實際值
}

private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
AreaDataBind(comboBox2, comboBox1.SelectedValue.ToString());
}

private void comboBox2_SelectedIndexChanged(object sender, EventArgs e)
{
AreaDataBind(comboBox3, comboBox2.SelectedValue.ToString());
}

DateTime類型比較大小：