过程或函数需要未提供的参数“@ID”

Question

我的源代码给了我一个错误：

过程或函数“spGetImageById”需要参数“@Photo_ID”， 没有提供。

我的存储过程如下所示：

GO
/****** Object:  StoredProcedure [dbo].[spGetImageById]    Script Date: 2018-01-13 18:14:55 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER procedure [dbo].[spGetImageById]
@Photo_ID int
as
Begin
    Select Photo_Data  
    from tblImages where Photo_ID=@Photo_ID
End

后端代码：

protected void Page_Load(object sender, EventArgs e) {

        string cs = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
        using (SqlConnection con = new SqlConnection(cs)) {
            SqlCommand cmd = new SqlCommand("spGetImageById", con);
            cmd.CommandType = CommandType.StoredProcedure;  

            SqlParameter paramId = new SqlParameter()
            {
                ParameterName = "@Photo_ID",
                Value = Request.QueryString["Photo_ID"]
            };
            cmd.Parameters.Add(paramId);

            con.Open();
            byte[] bytes = (byte[])cmd.ExecuteScalar();
            string strBase64 = Convert.ToBase64String(bytes);
            Image1.ImageUrl = "data:Image/png;base64," + strBase64;
            con.Close();
        }

    }

错误发生在以下行：

"byte[] bytes = (byte[])cmd.ExecuteScalar();".

您知道导致问题的原因吗？我已经失去了所有的希望......

Answer 1

确保您从Request.QueryString["Photo_ID"] 获得价值。尝试传递硬编码值进行测试。

加上传递参数一个有效的SqlDbType

        SqlParameter paramId = new SqlParameter()
        {
            ParameterName = "@Photo_ID",
            SqlDbType = SqlDbType.Int,
            Value = Request.QueryString["Photo_ID"]
        };