Question

我需要接受用户名并返回密码和用户ID，以确定他们是否有权访问项目中的特定表单。

我搜索了一个解决方案，并在此网站上查看了类似的问题，但无济于事。如果可以的话请帮忙。

在SQL Server调试中运行时返回的参数值为：

Joseph 
0x6D616368696E653100000000000000000000000000000000000000000000000000000000000000000000
34DFCAA9-1A5F-4AC4-AC43-4A025DD84063

我的存储过程是：

CREATE PROCEDURE [dbo].[RMVerifyUser] 
    @UserName AS VARCHAR(40),
    @Password AS BINARY(42) OUTPUT,
    @ClerkID AS UNIQUEIDENTIFIER OUTPUT
AS
    SELECT   
        @ClerkID = IDClerk,
        @Password = (CONVERT(binary(8), ClkPassCode, 0))    // ClkPassCode is varchar(50) in the table.
    FROM 
        tblClerkInfo
    WHERE
        ClkName = @UserName
        AND ISNULL(Canceled, 0) = 0

    RETURN

我的C＃代码是：

private string retrievePassword(object userName) 
{
    string strPassword = "";
    //uidClerkID = new Guid();

    connect.Open();

    try
    {
        SqlCommand command = new SqlCommand("RMVerifyUser");
        command.Connection = connect;
        command.CommandType = CommandType.StoredProcedure

        SqlParameter retUserName = new SqlParameter("@UserName", userName); // userName is passed in from another method. 
        retUserName.ParameterName = "@UserName";
        retUserName.Value = userName;
        command.Parameters.Add(retUserName); 

        SqlParameter retPassword = new SqlParameter("@Password", strPassword);   // I suspect the error is occurring somewhere in the declaration/definition of this parameter.
        retPassword.ParameterName = "@Password";
        retPassword.Direction = ParameterDirection.Output;
        retPassword.DbType.Equals(DbType.String);   
        retPassword.Size = 50;
        retPassword.Value = strPassword; 
        command.Parameters.Add(retPassword);  // ClkPassCode is nvarchar(50) in the data table.

        SqlParameter retUserID = new SqlParameter("@ClerkId", uidClerkID);  // uidClerkID is a property in a separate class, but I also tried - uidClerkID = new Guid() - in this method. Same error thrown.  
        retUserID.ParameterName = "@ClerkId";
        retUserID.Direction = ParameterDirection.Output;
        retUserID.Value = uidClerkID;
        command.Parameters.Add(retUserID);

        command.ExecuteNonQuery();

        uidClerkID = Guid.Parse(retUserID.Value.ToString());

        if (strPassword == DBNull.Value.ToString())
        {
            ReferenceEquals(strPassword, null);             
        }
        else
        {
            strPassword = retPassword.Value.ToString();
            return strPassword;
        }
    }
    catch (Exception ex)
    {
        ....
    }
}

Answer 1

您的存储过程以binary(42)作为参数类型，但在您的代码中，您“尝试”将其设置为DbType.String。更新代码以使用二进制文件。您还需要使用byte[]作为局部变量。另请注意，您应该设置DbType的值，在这种情况下，我使用了SqlDbType，因为它比DbType更具体。你正在做一个没有影响的平等比较。

byte[] password = new byte[42];

try
{
    // begin changed code

    SqlParameter retPassword = new SqlParameter("@Password", password);
    retPassword.Direction = ParameterDirection.Output;
    retPassword.SqlDbType = SqlDbType.Binary;
    retPassword.Size = 42;
    command.Parameters.Add(retPassword);

    // end changed code

    command.ExecuteNonQuery();


    // read the value back from the parameter
    password = retPassword.Value != DBNull.Value ? (byte[]) retPassword.Value : null;

Answer 2

我认为你的密码字段应该是nvarchar而不是binary。是否存在将varchar转换为二进制的隐式方法？我猜不会，我想你必须创建一个特殊的函数才能得到这种行为。

declare @binarydata binary
declare @password varchar(50)
set @binarydata = @password

请注意我们尝试执行此操作时出现的错误。

消息257，级别16，状态3，行4从数据类型隐式转换不允许varchar到二进制。使用CONVERT函数运行它查询。

无法在C＃中将SQL Server varchar转换为二进制文件

2 个答案: