System.TypeInitializationException引用DLL時

Question

我試圖創建一個.dll的形式的數據框架，以便我可以在創建新項目時參考它，而不是重新發明與我創建的每個項目的車輪。

我有一個app.config用於存儲我的SQL連接，一個使用app.config構建我的SQL ConnectionString（ConnectionStrings.cs）和一個Logic類（Logic.cs）的類，它將構建任何我需要從SQL Server中獲取對象。

下面是.dll文件的類：

ConnectionStrings.cs：

using System.Configuration; 
using System.Data.SqlClient; 

namespace DataFramework 
{ 
    public static class ConnectionStrings 
    { 
     static string _liveConnectionString = ConfigurationManager.ConnectionStrings["LiveDataSource"].ConnectionString; 
     static string _liveMISConnectionString = ConfigurationManager.ConnectionStrings["LiveDataSource_MIS"].ConnectionString; 
     static string _devConnectionString = ConfigurationManager.ConnectionStrings["DevDataSource"].ConnectionString; 
     static string _devMISConnectionString = ConfigurationManager.ConnectionStrings["DevDataSource_MIS"].ConnectionString; 

     public static SqlConnection CreateLiveConnection 
    { 
     get { return new SqlConnection(_liveConnectionString); } 
    } 

    public static SqlConnection CreateLiveMISConnection 
    { 
     get { return new SqlConnection(_liveMISConnectionString); } 
    } 

    public static SqlConnection CreateDevConnection 
    { 
     get { return new SqlConnection(_devConnectionString); } 
    } 

    public static SqlConnection CreateDevMISConnection 
    { 
     get { return new SqlConnection(_devMISConnectionString); } 
    } 
    } 
} 

Logic.cs：

using System; 
using System.Threading.Tasks; 
using System.Data; 
using System.Data.SqlClient; 

namespace DataFramework 
{ 
    public class Logic 
    { 

    SqlConnection liveConnection = ConnectionStrings.CreateLiveMISConnection; 
    SqlConnection devMISConnection = ConnectionStrings.CreateDevMISConnection; 

    public bool IsConnecting { get; set; } 
    public string ConnectionMessage { get; set; } 

    public async Task<DataTable> ResultDataTable(bool connectToLive, string commandText, CommandType commandType) 
    { 
     DataTable dt = new DataTable(); 
     using (SqlCommand command = new SqlCommand()) 
     { 
      try 
      { 
       command.CommandType = commandType; 
       command.CommandTimeout = 360000000; 

       switch (connectToLive) 
       { 
        case true: 
         command.CommandText = commandText; 

         command.Connection = liveConnection; 

         if (liveConnection.State == ConnectionState.Connecting) 
         { 
          IsConnecting = true; 
          ConnectionMessage = "Connecting to Data Source..."; 
         } 
         if (liveConnection.State != ConnectionState.Closed) 
          liveConnection.Close(); 
         if (liveConnection.State != ConnectionState.Open) 
         { 
          liveConnection.Open(); 
          IsConnecting = false; 
          ConnectionMessage = ""; 
         } 
         break; 
        case false: 
         command.CommandType = commandType; 
         command.CommandText = ""; 
         command.Connection = devMISConnection; 
         if (devMISConnection.State == ConnectionState.Connecting) 
         { 
          IsConnecting = true; 
          ConnectionMessage = commandText; 
         } 
         if (devMISConnection.State != ConnectionState.Closed) 
          devMISConnection.Close(); 
         if (devMISConnection.State != ConnectionState.Open) 
         { 
          devMISConnection.Open(); 
          IsConnecting = false; 
          ConnectionMessage = ""; 
         } 
         break; 
       } 

       using (SqlDataReader reader = await command.ExecuteReaderAsync()) 
       { 
        dt.Load(reader); 
       } 

      } 
      catch (Exception ex) 
      { 
       System.Windows.Forms.MessageBox.Show(ex.Message, "An Error Has Occured", System.Windows.Forms.MessageBoxButtons.OK, System.Windows.Forms.MessageBoxIcon.Error); 
      } 
      finally 
      { 
       if (devMISConnection.State != ConnectionState.Closed) 
        devMISConnection.Close(); 

       if (liveConnection.State != ConnectionState.Closed) 
        liveConnection.Close(); 
      } 
     } 

     return dt; 

    } 
} 
} 

包括我這個DLL作爲應用程序的參考，我正在寫作：

using System.Data; 
using System.Threading.Tasks; 
using System.Windows.Forms; 
using DataFramework; 

namespace WindowsFormsApplication1 
{ 
    public partial class Form1 : Form 
    { 
    DataTable dt = new DataTable(); 
    DataFramework.Logic logic = new Logic(); 

    public Form1() 
    { 
     InitializeComponent(); 
    } 

    private async void Form1_Load(object sender, EventArgs e) 
    { 
     dt = await Task.Run(() => logic.ResultDataTable(true, "SELECT * FROM MIS.dbo.ETL_Table", CommandType.StoredProcedure)); 
    } 
} 
} 

代碼拋出異常的位置：

SqlConnection liveConnection = ConnectionStrings.CreateLiveMISConnection; 

那麼，爲什麼，當我初始化類，我能得到這個問題呢？

Answer 1

當您從另一個項目中引用DLL（或項目）時，將使用最頂端項目的app.config。所以，如果你的WinFrameApp被調用了你的DataFramework，那麼你的WinformsApp需要在其中有正確的配置設置。默認情況下，它將忽略DataFramework中的任何app.config。有時有點令人沮喪！將您的設置從您的DataFramework app.config複製到WinformsApp app.config，它將起作用。

另一個無關的觀察是，您具備以下條件：

"SELECT * FROM MIS.dbo.ETL_Table", CommandType.StoredProcedure 

命令類型應該是文本，而不是一個存儲過程。