C# Error \"The type initializer for … threw an exc

问题:

This error occurs only in some computers. By reading the stack information, there is some problem when I call to this static method ("FormatQuery") in a static class:

using System;
using System.Collections.Generic;
using System.Data;
using System.Diagnostics;
using System.IO;
using System.Text;
using System.Windows.Forms;
using DevExpress.XtraEditors;
using FlexCel.Report;
using FlexCel.XlsAdapter;
using ComboBox=System.Windows.Forms.ComboBox;

namespace XSoftArt.A
{
    static class RHelper
    {
        private static string FormatQuery(string FieldName, int Count,
            CheckedListBox chekedListBox)
        {
            string ID = string.Empty;
            int n = Count;

            foreach (DataRowView item in chekedListBox.CheckedItems)
            {
                ID = ID + item["" + FieldName + ""];
                if (n > 1)
                {
                    ID = ID + " , ";
                    n--;
                }
            }
            return ID;
        }

        public static string FormatQuery(CheckedListBox chekedListBox)
        {
            return FormatQuery(chekedListBox.ValueMember,
                chekedListBox.CheckedItems.Count, chekedListBox);
        }
    }

So, what's the problem? How do I solve it? Is there something wrong with the project configuration or debbuging mode or what?

Error information:

   at XSoftArt.EVS.ReportHelper.FormatQuery(CheckedListBox chekedListBox)
   at XSoftArt.EVS.NewEmailSelectClient.LoadList_v2(String search, TextBox txtbox)
   at XSoftArt.EVS.NewEmailSelectClient.LoadContacts()
   at XSoftArt.EVS.NewEmailSelectClient.button7_Click(Object sender, EventArgs e)
   at System.Windows.Forms.Control.OnClick(EventArgs e)
   at System.Windows.Forms.Button.OnClick(EventArgs e)
   at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
   at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.ButtonBase.WndProc(Message& m)
   at System.Windows.Forms.Button.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

回答1:

I tried your code:

CheckedListBox cb = new CheckedListBox();
for (var i = 1; i < 11; i++)
  cb.Items.Add("Item " + i, i % 3 == 0);

string fmt = RHelper.FormatQuery(cb);
Console.WriteLine(fmt);
Console.ReadLine();

It threw an exception at this line:

foreach (DataRowView item in chekedListBox.CheckedItems)

// Unable to cast object of type 'System.String' to type 'System.Data.DataRowView'.

Maybe you are also facing the same kind of problem. Instead of casting to DataRowView, try making the following changes:

foreach (var item in chekedListBox.CheckedItems)
{
    ID = ID + item.ToString(); // item["" + FieldName + ""];

Because items in CheckedListBox are of object type.

回答2:

A Type Initializer exception indicates that the type couldn't be created. This would occur typically right before your call to your method when you simply reference that class.

Is the code you have here the complete text of your type? I would be looking for something like an assignment to fail. I see this a lot with getting app settings and things of that nature.

static class RHelper
{
     //If this line of code failed, you'd get this error
     static string mySetting = Settings.MySetting;
} 

You can also see this with static constructors for types.

In any case, is there any more to this class?

回答3:

I had the same error but in my case it was caused by mismatch in platform target settings. One library was set specifically to x86 while the main application was set to 'Any'...and then I moved my development to an x64 laptop.

回答4:

I got this error when I modified an Nlog configuration file and didn't format the XML correctly.

回答5:

This problem can occur if a class tries to get value of a non-existent key in web.config.

For example, the class has a static variable ClientID

private static string ClientID = System.Configuration.ConfigurationSettings.AppSettings["GoogleCalendarApplicationClientID"].ToString();

but the web.config doesn't contain the 'GoogleCalendarApplicationClientID' key, then the error will be thrown on any static function call or any class instance creation

回答6:

I got this error with my own code. My problem was that I had duplicate keys in the config file.

回答7:

I got this error when trying to log to an NLog target that no longer existed.

回答8:

If you have web services, check your URL pointing to the service. I had a simular issue which was fixed when I changed my web service URL.

回答9:

This can be caused by not having administrator permissions for Oracle Client. Add this in App.config file:

<IPermission class="Oracle.DataAccess.Client.OraclePermission,
 Oracle.DataAccess, Version=2.111.7.20, Culture=neutral,
 PublicKeyToken=89b483f429c47342" version= "1" Unrestricted="true"/>

回答10:

I had this problem and like Anderson Imes said it had to do with app settings. My problem was the scope of one of my settings was set to "User" when it should have been "Application".

回答11:

This error was generated for me by having an incorrectly formatted NLog.config file.