.net load configuration in class library

问题

let's say i have : 1) 1 WindowsForm on "A" Project 2) 1 WindowsForm on "B" Project 3) 1 class library (GAC)

Condition Both of Project references is same

Part 1 : I have my.settings in my class library to save configuration with public function

Part 2 : I create value/configuration from "A" and store it in my class library. settings has been successfully saved, and load the value/configuration with no errors

Question : 1). Why i can't load the value/configuration from "B" ? NullException shown First I think, to use my.resources in class library but, my.resources is readonly

2). What best solution to connecting 1 class library to multiple project

code in class library to save value

Public Sub Kucing_simpan(ByVal value As String)
    My.Settings.Kucing = value
    My.Settings.Save()
End Sub

code in class library to load value

Public Function kucing_ambil()
    Dim value As String
    value = My.Settings.Kucing
    Return value
End Function

code in "A"

dim save as new Zombie.Kencing 'My class Library Name
save.Kucing_simpan(textbox1.text)

code in "B"

dim load as new Zombie.Kencing 'My class Library Name
DataGridView1.Rows(0).Cells(1).Value = load.kucing_ambil

回答1:

You cant do what you are trying to do - at least not the way you are going about it.

First, you have to understand how/where Settings are saved. With default naming of the app and such, project A - WindowsApplication1 will save its settings to something cryptic such as:

C:\Users\<UserName>\AppData\Local\Microsoft\_
    WindowsApplication1_Url_ggn13vigzyicmtfkwaa3vi5tyxn0sy3r\1.0.0.0\user.config

NET creates the hash to make sure that apps with the same name have a different safe location to store settings. So, WindowsApplication3 will have a different hash; this is also how your 17th project with the name WindowsApplication1 doesnt accidentally load or find the settings of WinApp 1-16.

Next, your Settings Class Lib is not a separate application. As a DLL, it is operating as if it was a set of functions and such associated with the App calling it. So when Project A saves settings thru the ClassLib, they are saved to a different location than Project B. Even using a Class Lib, NET uses Application credentials and info to concoct the filename and path.

What you can do is write a Class which defines all the possible settings (or creates a List or Dictionary of them) then save to a fixed, known location such as:

Private Comp As String = "ZiggySoft"
Private Prod As String = "ZiggyWare"

Private settingsFile As String

'...
settingsfile = Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData)
settingsfile = Path.Combine(settingsfile, Comp, Prod, "usersettings.dat")

This will result in: "C:\Users\\AppData\Roaming\ZiggySoft\ZiggyWare\usersettings.dat"

Include the same file in each project (Add Existing Item, maybe pick Add As Link from the dropdown). Now, you can read and write your Settings to a file you are in charge of. You can save/load the entire class or List in 3-5 lines of code if you serialize it.

When Project A loads the settings, it would also get those which only apply to B or J or V, but common ones would and could be shared.

来源：https://stackoverflow.com/questions/26076985/net-load-configuration-in-class-library

标签

vb.net

class-library