Data binding in WPF datagrid control using mysql server database

Question

1.00/5 (2 votes)

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I'm trying to import datatable from MySQL to datagrid wpf .

But error ('Null Reference exception was unhandled by user code 'Object reference not set to an instance of an object.' Pin) shows at this line code :

C#

string ConString = ConfigurationManager.ConnectionStrings["ConString"].ConnectionString;

I think it's a configuration problem , but my connection information are correct !

What I have tried:

I followed the steps in this article :

www.codeproject.com/Tips/362436/Data-binding-in-WPF-DataGrid-control?msg=5389895#xx5389895xx

and this is my APP.config

XML

<?xml version="1.0" encoding="utf-8" ?>

<configuration>

    <connectionStrings>
      <add connectionString ="SERVER=; DATABASE=; UID=; PASSWORD= ;" name="ConString"/>
    </connectionStrings>

</configuration>

I'm a beginner In WPF ,Thank you for any help :) Sorry for my bad English .

Posted 26-Apr-17 22:29pm

EM_Y

Updated 27-Apr-17 22:40pm

v5

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CHill60 27-Apr-17 6:19am

Two questions...
1. Is that < pre lang="xml"> in your question actually in your App.Config file or did that happen as a result of posting the file into the question?
2. Are you absolutely sure that is the line that throws the exception.

EM_Y 27-Apr-17 6:23am

1. yes it's Xml in App.config
2. yes the error shows at this line :
string ConString = ConfigurationManager.ConnectionStrings["ConString"].ConnectionString;

CHill60 27-Apr-17 7:45am

If you want to respond to a comment then use the Reply button next to it so that the poster is notified.

Well, you have changed the content of your post, so the answer to my first question was not "it's the xml in the app.config" - it should have been "that happened when I posted my code into CodeProject"

When I use your code with your app.config I am unable to reproduce the problem. Try putting a breakpoint on the next line and run the program; then in the Immediate Window of the IDE type ? ConfigurationManager.ConnectionStrings["ConString"].ToString() and let me know what is shown or what error occurs then.

EM_Y 28-Apr-17 3:20am

I got zero error , but the debugging stopped at the same line :
string ConString = ConfigurationManager.ConnectionStrings["ConString"].ConnectionString;

EM_Y 28-Apr-17 3:40am

Problem solved ,My mistake was that I created new APP.config while I already have one !
Thank you for your time and help , I will do my best to focus more :)

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CHill60 · Accepted Answer · 2017-04-27T22:40:00

Solution 2

Posting solution to close off post. OP has confirmed that the problem is resolved. A second copy of App.config was causing the problem.

Posted 27-Apr-17 22:40pm

CHill60