[英]Failure to convert SQL Server varchar to binary in C#
我需要接受一個用戶名並返回密碼和用戶ID,以確定他們是否有權訪問項目中的特定表單。
我已經在該網站上搜索了解決方案並查看了類似的問題,但無濟於事。 如果可以的話請幫忙。
在SQL Server調試中運行時返回的參數值為:
Joseph
0x6D616368696E653100000000000000000000000000000000000000000000000000000000000000000000
34DFCAA9-1A5F-4AC4-AC43-4A025DD84063
我的存儲過程是:
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#代碼是:
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)
{
....
}
}
您的存儲過程將binary(42)
作為參數類型,但是在代碼中您“嘗試”將其設置為DbType.String
。 更新您的代碼以使用二進制。 您還需要對本地變量使用byte[]
。 還要注意,您應該設置DbType
的值,在這種情況下,我使用SqlDbType,因為它比DbType
更具體。 您正在進行沒有影響的相等比較。
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;
我認為您的密碼字段應為nvarchar而不是二進制。 是否有將varchar轉換為二進制的隱式方法? 我猜不會,我想您必須創建一個特殊的函數才能獲得此行為。
declare @binarydata binary
declare @password varchar(50)
set @binarydata = @password
請注意,嘗試執行此操作時會收到錯誤消息。
消息257,級別16,狀態3,第4行不允許從數據類型varchar隱式轉換為二進制。 使用CONVERT函數運行此查詢。
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