连接数据库
<appSettings>
 <add key="sqllink" value="server=yfq-001;uid=ADM;pwd=sdadm;database=DBMT50"></add>
 <add key="sqllink1" value="server=ymc;uid=sa;pwd=;database=Northwind"></add>
</appSettings>
打开连接
string connstr=System.Configuration.ConfigurationSettings.AppSettings["sqllink"];
SqlConnection conn=new SqlConnection(connstr);
conn.Open();
添加DataGrid
SqlDataAdapter dr=new SqlDataAdapter(sqlstr,conn);
DataSet ds=new DataSet();
dr.Fill(ds,"usract");
if(Convert.ToInt32(ds.Tables["ContList"].Rows.Count.ToString())==0)
{
    this.DataGrid1.ShowFooter=true;
}
this.DataGrid1.DataSource=ds.Tables["usract"].DefaultView;
this.DataGrid1.DataBind(); 
ADO.NET应用
string sql="select count(*) as icount from sysoper where logname='"+this.usrname.Text+"'";
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