c# connection string and concatenation app.config

Question

I have the following connection string through which i connect to an Access database(.mdb) located in a sub-folder inside the root-folder of my application :

 OleDbConnection con = new OledbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + System.AppDomain.CurrentDomain.BaseDirectory() + "Data\rctts.mdb;Jet OLEDB:Database Password=mypassword;")

My question is, how do i put the connection string in the app.config file? Generally, i use :

 <connectionStrings>
    <add name="Test" connectionString="Data Source=.;Initial Catalog=OmidPayamak;Integrated Security=True" providerName="System.Data.SqlClient" />
</connectionStrings>

The issue i am facing is that in my connection string, i am doing some concatenations and also using System.AppDomain.CurrentDomain.BaseDirectory() to set the Data Source... How do i do the same concatenation in app.config ? Is it possible to do so ?

That looks like VB.Net concatenation, not C#.

juharr
– juharr

2018-05-30 14:20:56 +00:00
Commented May 30, 2018 at 14:20 — juharr
– juharr, Commented May 30, 2018 at 14:20
@juharr , now it looks like c# :)

Aousaf Rashid
– Aousaf Rashid

2018-05-30 14:22:50 +00:00
Commented May 30, 2018 at 14:22 — Aousaf Rashid
– Aousaf Rashid, Commented May 30, 2018 at 14:22

Aousaf Rashid · Accepted Answer · 2018-06-04 18:54:25Z

3

You could try the following:

connectionString="Data Source=|DataDirectory|\rctts.mdb;Initial Catalog=OmidPayamak;Integrated Security=True"

and then try to set the value of DataDirectory as below:

var currentDomain = AppDomain.CurrentDomain;
var basePath = currentDomain.BaseDirectory;
currentDomain.SetData("DataDirectory", basePath+"\Data");

at the corresponding startup file of your application.

edited Jun 4, 2018 at 18:54

Aousaf Rashid

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answered May 30, 2018 at 14:10

Christos

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14 Comments

Aousaf Rashid Over a year ago

don't mind me asking, i don't see the app.config part here?

Christos Over a year ago

The app config part is the first one. In the app config you would just replace "Data Source=..." with the above.

Aousaf Rashid Over a year ago

can you explain what |Data Directory| means here? is it working like a variable which is expecting values?

Christos Over a year ago

@zackraiyan Exactly ! It is variable that can be set trough AppDomain. Please check this blogs.msdn.microsoft.com/smartclientdata/2005/08/26/…

Aousaf Rashid Over a year ago

@Christos , understood

|

Sergey Kalinichenko · Accepted Answer · 2018-05-30 14:56:19Z

3

Although configuration APIs offer no facilities to manipulate connection strings for you, you could place connection string "template" into configuration, and do the rest of manipulation in your code using string.Format:

Config:

<connectionStrings>
    <add name="Test" connectionString="Data Source={0}Data\rctts.mdb;Initial Catalog=OmidPayamak;Integrated Security=True" providerName="System.Data.SqlClient" />
</connectionStrings>

C# code:

string conStr = string.Format(
    ConfigurationManager.ConnectionStrings["Test"].ConnectionString
,   System.AppDomain.CurrentDomain.BaseDirectory()
);

edited May 30, 2018 at 14:56

answered May 30, 2018 at 14:10

Sergey Kalinichenko

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2 Comments

Aousaf Rashid Over a year ago

i am getting a warning : Runtime error may occur when converting 'ConnectionStringSetting' to 'IFormatProvider' , should i be worried?

Sergey Kalinichenko Over a year ago

@zackraiyan That's right - I forgot to add .ConnectionString. That's what happens when I do not try to compile things locally. Thank you!

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