Question

此行代码出现错误：

int records = (int)cmd.ExecuteScalar();

错误是：

非法的变量名称/数字

完整代码：

string strq = "select count(*) from groupmembers where group_members='" + txtgrpmem.Text + "'";
cmd = new OracleCommand(strq, Dbconn);
cmd.Parameters.AddWithValue("group_members", txtgrpmem.Text);

if (Dbconn.State == ConnectionState.Closed)
{
    Dbconn.Open();
}

int records = (int)cmd.ExecuteScalar();

if (records == 0)
{
}
else
{
}

Answer 1

我相信您的查询需要包含这样的group_members参数：

    string strq = "select count(*) from groupmembers where group_members=:group_members";

注意：参数名称以冒号（:)开头

Answer 2

错误是因为您在group_members中使用了参数OracleCommand，但是在查询中没有使用参数。在此处查看Parameterised Query。另外，请检查OracleCommand.ParameterCheck

的链接

string strq = "select count(1) from groupmembers where group_members=:group_members";

using (OracleConnection Dbconn = new OracleConnection(CONNECTION_STRING))
{
   if (Dbconn.State == ConnectionState.Closed)
   {
      Dbconn.Open();
   }

   using (OracleCommand cmd = new OracleCommand(strq, Dbconn))
   {
       cmd.Parameters.AddWithValue("group_members", txtgrpmem.Text);

       int records = (int)cmd.ExecuteScalar();
   } 
}

还有why using?

int记录错误=（int）cmd.ExecuteScalar（）;非法的变量名称/编号

2 个答案: