C＃选择Transact-SQL（表列属性）

Question

我想选择使用c＃的表列属性。我写了这段代码。我的查询正在处理sqlserver。但我不会在C＃中获得最大长度。

我的查询是这里

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

结果是在这里：

我的C＃代码这里：

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(); 
        } 

结果（x = -1）

如何在c＃中获得长度。

请帮忙！

Answer 1

检查你的查询是否正确

更改ConnectionString，以匹配你所拥有的 - 例如：

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

，并使用下面的代码：

 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等类与SQL Server进行通信。

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(); 
}