读写xml文件的问题.
我在winform下登陆的时候,第一次登陆的时候要配置连接字符串,即配置app.config文件(用xml写),
但是我在写完后,在点击登陆他会弹出connectionstring没有初始化,其实app.config文件已经修改了,
但是好像没有加载到当前的程序中,也即再次登陆后就可以正常登陆了.不知道如何在第一次就可以让他能够登陆 代码如下:
private void button1_Click(object sender, System.EventArgs e)
{
SqlConnection myconn = new SqlConnection(ConfigurationSettings.AppSettings["ConnectionString"]);
// SqlCommand mycom = new SqlCommand("select * from employee",myconn);
SqlDataAdapter sa = new SqlDataAdapter("select * from employee",myconn);
DataSet ds = new DataSet();
sa.Fill(ds,"ab");
this.dataGrid1.DataSource = ds.Tables[0];
}
public void SetXmlFileValue(string xmlPath,string AppKey,string AppValue)//写xmlPath是文件路径+文件名,AppKey是 Key Name,AppValue是Value
{
XmlDocument xDoc = new XmlDocument();
xDoc.Load(xmlPath);
XmlNode xNode;
XmlElement xElem1;
XmlElement xElem2;
xNode = xDoc.SelectSingleNode("//appSettings");
xElem1 = (XmlElement)xNode.SelectSingleNode("//add[@key='" + AppKey + "']");
if ( xElem1 != null )
{
xElem1.SetAttribute("value",AppValue);
}
else
{
xElem2 = xDoc.CreateElement("add");
xElem2.SetAttribute("key",AppKey);
xElem2.SetAttribute("value",AppValue);
xNode.AppendChild(xElem2);
}
xDoc.Save(xmlPath);
}
private void button2_Click(object sender, System.EventArgs e)
{
this.connstring = "server="+this.textBox2.Text+";database="+this.textBox1.Text+";uid="+this.textBox3.Text+";pwd="+this.textBox4.Text;
string xmlpath = "..\\..\\app.config";
this.SetXmlFileValue(xmlpath,"ConnectionString",connstring);
MessageBox.Show("保存设置成功!");
}