学步园

1、获取本机所有IP显示到combobox，并初始化combobox为第一个IP，还需要过滤掉回环IP

IPAddress[] hostIpList = Dns.GetHostAddresses(Dns.GetHostName());
//comboBox1.Text = string.Empty;
comboBox1.ResetText();
comboBox1.SelectedIndex = -1;
foreach (IPAddress ip in hostIpList)
{
    Console.WriteLine("Ip[]: {1}", ip.ToString());
    if (IPAddress.IsLoopback(ip) != true)
        comboBox1.Items.Add(ip.ToString());
}
comboBox1.SelectedIndex = 0;

2、判断combobox是否有内容，以及某个Item是否为空

if (this.comboBox1.Items.Count > 0)
{
        String s = this.comboBox1.Items[0].ToString();
        if (String.IsNullOrEmpty(s) == false)
                comboBox1.SelectedIndex = 0;
        else
                MessageBox.Show("Host's ipaddress is empty!");
}
else
{
        MessageBox.Show("Can not get any host's ipaddress!\n" + 
                        "Please press CANCEL to cancel!",
                        "ERROR");//, MessageBoxButtons.OKCancel);
}

3、messageBox控件使用介绍

      来源:  http://www.cnblogs.com/Tammie/archive/2011/08/05/2128623.html

    // 标题为空, 按钮只显示OK
    MessageBox.Show("Hello~~~~");
    // 标题为"ERROR", 按钮只显示OK
    MessageBox.Show("There are something wrong!","ERROR");
    // 自定义消息盒 消息标题"Confirm Message", 按钮有两个: OK 和 Cancel
    if (MessageBox.Show("Delete this user?", "Confirm Message",MessageBoxButtons.OKCancel) == DialogResult.OK)
    // 带有ICON的message
    if (MessageBox.Show("Delete this user?", "Confirm Message",MessageBoxButtons.OKCancel,MessageBoxIcon.Question) == DialogResult.OK)
    // 默认为cancel按钮的方法
    if (MessageBox.Show("Delete this user?", "Confirm Message", MessageBoxButtons.OKCancel,MessageBoxIcon.Question,MessageBoxDefaultButton.Button2) == DialogResult.OK)
    // 反向显示, 类似于ubuntu里的那种按钮效果
    if (MessageBox.Show("Delete this user?", "Confirm Message", MessageBoxButtons.OKCancel,MessageBoxIcon.Question,MessageBoxDefaultButton.Button2,MessageBoxOptions.RtlReading) ==DialogResult.OK)
    // 添加help按钮
    if (MessageBox.Show("Delete this user?", "Confirm Message", MessageBoxButtons.OKCancel,MessageBoxIcon.Question, MessageBoxDefaultButton.Button2, MessageBoxOptions.RightAlign,true) ==DialogResult.OK)
    // 指定帮助文件的路径
    if (MessageBox.Show("Delete this user?", "Confirm Message", MessageBoxButtons.OKCancel,MessageBoxIcon.Question, MessageBoxDefaultButton.Button1, MessageBoxOptions.RtlReading,@"/folder/file.htm") == DialogResult.OK)
    //HelpNavigator指定常数来指示要显示的帮助文件元素, Find帮助文件将打开到搜索页
    if (MessageBox.Show("Delete this user?", "Confirm Message", MessageBoxButtons.OKCancel,MessageBoxIcon.Question, MessageBoxDefaultButton.Button1, MessageBoxOptions.RtlReading,@"/folder/file.htm", HelpNavigator.Find) == DialogResult.OK)

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