使用参数查旬，结果绑定到gridview有有关问题！

使用参数查旬，结果绑定到gridview有问题！！！
由于考虑到安全性，使用参数查询。
        string   cmdCode   =   "select   *   from   KHGL_Customer   where   cCusCode=@cCusCode ";
        OleDbDataAdapter   daCode   =   new   OleDbDataAdapter(cmdCode,   myconnection);
        OleDbCommand   mycommand   =   new   OleDbCommand(cmdCode,   myconnection);
        mycommand.Parameters.Add(new   OleDbParameter( "@cCusCode ",   OleDbType.VarChar,   20));
                                mycommand.Parameters[ "@cCusCode "].Value   =   txtSearch.Text;
                                myconnection.Open();
                                DataSet   dsCode   =   new   DataSet();
                                daCode.Fill(dsCode,   "KHGL_Customer ");
                                GridView1.DataSource   =   dsCode;
                                GridView1.DataBind();
                                myconnection.Close();
这一句daCode.Fill(dsCode,   "KHGL_Customer ");提示：至少一个参数没有被指定值。如果不使用参数就一点问题也没有。怎么解决？？？

[解决办法]
string cmdCode = "select * from KHGL_Customer where cCusCode=@cCusCode ";

OleDbCommand mycommand = new OleDbCommand(cmdCode, myconnection);
mycommand.Parameters.Add(new OleDbParameter( "@cCusCode ", OleDbType.VarChar, 20));
mycommand.Parameters[ "@cCusCode "].Value = txtSearch.Text;

OleDbDataAdapter daCode = new OleDbDataAdapter(mycommand);//这里
myconnection.Open();
DataSet dsCode = new DataSet();
daCode.Fill(dsCode, "KHGL_Customer ");
GridView1.DataSource = dsCode;
GridView1.DataBind();
myconnection.Close();