將varchar值「..」轉換爲數據類型int時的轉換失敗

問題出在可變小時，當我嘗試在CmdString中使用時引發異常。我不明白爲什麼在變量小時是字符串時拋出異常。我怎麼解決這個問題。我在這裏錯過了什麼。將varchar值「..」轉換爲數據類型int時的轉換失敗

string ConString = ConfigurationManager.ConnectionStrings["DbSystem"].ConnectionString; 
string CmdString = string.Empty; 

DateTime time = DateTime.Now; 
string hour = time.Hour.ToString(); 

using (SqlConnection con = new SqlConnection(ConString)) 
{ 
    string folderName = DateTime.Now.Day.ToString() + "-" + DateTime.Now.Month.ToString() + "-" + DateTime.Now.Year.ToString(); 
    string folder = Path.Combine(FOLDER_FOR_BACKUP_FILES); 
    Directory.CreateDirectory(FOLDER_FOR_BACKUP_FILES); 

    CmdString = @"declare @fileName varchar(100); declare @dbName varchar(100); declare @fileDate varchar(20); set @fileName = '" + folder + @"\'; set @dbName = 'DbSystem'; set @fileDate = convert(varchar(20), getdate(), 105); set @fileName = @fileName + @dbName + ' ' + @fileDate + '-' + " + hour + @" + '.bak'; backup database @dbName to disk = @fileName;"; 

    SqlCommand cmd = new SqlCommand(CmdString, con); 

    SqlDataAdapter sda = new SqlDataAdapter(cmd); 
    DataTable dt = new DataTable("*"); 
    sda.Fill(dt); 
}

來源

2015-10-16 Evgeni Velikov

您應該使用參數化查詢，而不是像SQL注入那樣構建您的命令字符串！看看這裏的答案：http://stackoverflow.com/questions/7505808/using-parameters-in-sql-statements – CeOnSql

你應該CONVERT您小時VARCHAR：

@fileDate + '-' + CONVERT(VARCHAR(20), " + hour + @") + '.bak';

雖然hour是在應用端的字符串，當它是由SQL Server的執行，這是一個INT。所以你需要隱含地包含一個CONVERT函數。

來源

2015-10-16 06:28:25

因爲小時現在是字符串。您可以將CmdString更改爲

CmdString = @"declare @fileName varchar(100); declare @dbName varchar(100); declare @fileDate varchar(20); set @fileName = '" + folder + @"\'; set @dbName = 'DbSystem'; set @fileDate = convert(varchar(20), getdate(), 105); set @fileName = @fileName + @dbName + ' ' + @fileDate + '-' + '" + hour + @"' + '.bak'; backup database @dbName to disk = @fileName;";

來源

2015-10-16 06:38:45

將varchar值「..」轉換爲數據類型int時的轉換失敗

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