c# - sql语法错误，以及与sql语法相关的字符串问题

嗨，当我在下面的代码中将idWallPosting添加到我的select语句中时，我收到了sqlsyntax错误：

using (OdbcCommand cmd = new OdbcCommand("SELECT idWallPosting, wp.WallPostings, p.PicturePath FROM WallPosting wp LEFT JOIN User u ON u.UserID = wp.UserID LEFT JOIN Pictures p ON p.UserID = u.UserID WHERE wp.UserID=" + userId + " ORDER BY idWallPosting DESC", cn))
    {
        using (OdbcDataReader reader = cmd.ExecuteReader())
        {
            test1.Controls.Clear();

            while (reader.Read())
            {

                System.Web.UI.HtmlControls.HtmlGenericControl div = new System.Web.UI.HtmlControls.HtmlGenericControl("div");
                div.Attributes["class"] = "test";


                div.ID = String.Format("{0}", reader.GetString(2));
                // this line is responsible, problem here and my sqlsntax, im trying to set the SELECT idWallPosting for the div ID
                Image img = new Image();
                img.ImageUrl = String.Format("{0}", reader.GetString(1));

                img.AlternateText = "Test image";

                div.Controls.Add(img);
                div.Controls.Add(ParseControl(String.Format("&nbsp&nbsp " + "{0}", reader.GetString(0))));
                div.Attributes.Add("onclick", "return confirm_delete();");

                div.Style["clear"] = "both";
                test1.Controls.Add(div);

            }
        }
    }

我的数据库看起来像这样：



在我的代码中，我试图将div.ID设置为WallPosting表中的当前idWallPosting，因此我也不确定我是否有正确的设置。

编辑：

错误：


  无法将类型为“ System.Int32”的对象转换为类型为“ System.String”的对象。


我认为与此行相关：

div.ID = String.Format("{0}", reader.GetString(2));

最佳答案

您需要一个逗号。这个：

using (OdbcCommand cmd = new OdbcCommand("SELECT idWallPosting wp.WallPostings, p.PicturePath FROM WallPosting wp LEFT JOIN User u ON u.UserID = wp.UserID LEFT JOIN Pictures p ON p.UserID = u.UserID WHERE wp.UserID=" + userId + " ORDER BY idWallPosting DESC", cn))

应该是这样的：

using (OdbcCommand cmd = new OdbcCommand("SELECT idWallPosting, wp.WallPostings, p.PicturePath FROM WallPosting wp LEFT JOIN User u ON u.UserID = wp.UserID LEFT JOIN Pictures p ON p.UserID = u.UserID WHERE wp.UserID=" + userId + " ORDER BY idWallPosting DESC", cn))

逗号：------------------------------------------------ -------------------------------------------------- -^

编辑：

您可以尝试使用GetValue而不是GetString。 GetValue的说明：


  以其本机格式获取指定序数列的值。

关于c# - sql语法错误，以及与sql语法相关的字符串问题，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/5489680/