C＃選擇Transact-SQL（表列屬性）

Question

我想選擇使用c＃的表列屬性。我寫了這段代碼。我的查詢正在處理sqlserver。但我不會在C＃中獲得最大長度。

我的查詢是這裏

//TableName:Contents, ColumnName : Title 
select Col_Length('Contents','Title') as columnLengthh 

結果是在這裏：

我的C＃代碼這裏：

string columnLength = "select Col_Length('Contents','Title') as columnLengthh"; 
        adapter = new SqlDataAdapter(columnLength, connection); 
        dataSet = new DataSet(); 
        adapter.Fill(dataSet); 
        DataTable dataTable2 = dataSet.Tables[0]; 
        foreach (DataRow row in dataTable2.Rows) 
        { 
         var x = row["columnLengthh"].ToString(); 
        } 

結果（x = -1）

如何在c＃中獲得長度。

請幫忙！

Answer 1

檢查你的查詢是否正確

更改ConnectionString，以匹配你所擁有的 - 例如：

string connectionString = @"server=localhost\mysqlserver;database=master;Trusted_Connection=True;"; 

，並使用下面的代碼：

 string queryString = "select Col_Length('Contents','Title') as columnLengthh"; 
     string connectionString = @"your con string"; 
     SqlConnection connection = null; 
     try 
     { 
      connection = new SqlConnection(connectionString); 

      using (SqlCommand command = new SqlCommand(queryString, connection)) 
      { 
       connection.Open(); 
       var result = command.ExecuteScalar(); 
       Console.WriteLine("columnLengthh = {0}", result); 
      } 
     } 
     catch (Exception ex) 
     { 
      ex.ToString(); 
     } 
     finally 
     { 
      connection.Close(); 
     } 

Answer 2

只需使用SqlConnection,SqlCommand,SqlReader等類與SQL Server進行通信。

string queryString = "select Col_Length('Contents','Title') as columnLengthh"; 
string connectionString = "Your connection string"; 
SqlConnection connection = null; 
try 
{ 
    connection = new SqlConnection(connectionString) 
    using (SqlCommand command = new SqlCommand(queryString, connection)) ; 
    { 
     connection.Open(); 
     var result = command.ExecuteScalar(); 
     Console.WriteLine("columnLengthh = {0}", result); 
    } 
} 
finally 
{ 
    connection.Close(); 
}