c#数据绑定之向查询中添加参数(.Net连接外部数据库)

在access数据库中可以用mssql的形式定义操作字符串，也可以采用oledb的形式。

mssql 形式

string sqltext = @"select * from [user] where username= @name";

oledb的形式

string sqltext = @"select * from [user] where username= ？";

下一步是通过 oledbcommand执行操作。

oledbcommand dataaction = new oledbcommand(sqltext,linkdb);

给参数赋值语句采用的方法为addwithvalue：

dataaction.parameters.addwithvalue("@name","wangyong");

完整代码如下：

using (oledbconnection linkdb = new oledbconnection(@" provider=microsoft.ace.oledb.12.0;data source=|datadirectory|\aimeili.accdb"))
            {
                linkdb.open();
                string sqltext = @"select * from [user] where username= @name";
                oledbcommand dataaction = new oledbcommand(sqltext,linkdb);
                dataaction.parameters.addwithvalue("@name","wangyong");
                try
                {
                    oledbdatareader scanitems = dataaction.executereader();
                    if (scanitems.hasrows)
                    {
                        while (scanitems.read())
                        {
                            messagebox.show(scanitems[1].tostring());
                        }
                    }

                }
                catch (exception ex)
                {
                    messagebox.show("failure" + ex.message);
                }
            }