How do I take a XML Document and display information into text boxes?

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I am trying to take an XML document that look it this.
My C# code.

public void loadXML()
{
	ProjectReferralTableControlRow rows = new ProjectReferralTableControlRow();



	System.Xml.XmlReader obj = System.Xml.XmlReader.Create(@"c:\temp\reg.xml");
	{
		obj.Read();
		obj.ReadStartElement("Registration");
		obj.ReadStartElement("BusinessName",  rows.SubConstructionManager1.Text);
		obj.ReadStartElement("OwnerName", rows.SubContactName1.Text);
		obj.ReadStartElement("Address", rows.SubAddress1.Text);
		obj.ReadStartElement("City", rows.SubCity1.Text);
		obj.ReadStartElement("State", rows.SubState1.Text);
		obj.ReadStartElement("Zipcode", rows.SubZip1.Text);
		obj.ReadStartElement("Phone", rows.SubPhone1.Text);
		obj.ReadStartElement("Fax", rows.SubFax1.Text);
		obj.ReadStartElement("EmailAddress", rows.SubEmail1.Text);

	}
	obj.ReadEndElement();								
}

getting the following error.

Object reference not set to an instance of an object.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 
Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.
Source Error: 


Line 979:                obj.Read();
Line 980:                obj.ReadStartElement("Registration");
<big></big>Line 981:                obj.ReadStartElement("BusinessName",  rows.SubConstructionManager1.Text);
Line 982:                obj.ReadStartElement("OwnerName", rows.SubContactName1.Text);
Line 983:                obj.ReadStartElement("Address", rows.SubAddress1.Text);

Posted 24-Feb-11 5:04am

postonoh

Updated 24-Feb-11 5:06am

Manas Bhardwaj

v2

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Comments

Nish Nishant 24-Feb-11 11:08am

Post the stack trace here.

postonoh 24-Feb-11 11:14am

NullReferenceException: Object reference not set to an instance of an object.]
Test.UI.Controls.TestPage.BaseProjectReferralTableControl.loadXML() in f:\Test\Test\App_Code\Test Page\TestPage.Controls.cs:981
Test.UI.Controls.TestPage.BaseProjectReferralTableControl..ctor() in f:\Test\Test\App_Code\Test Page\TestPage.Controls.cs:754
Test.UI.Controls.TestPage.ProjectReferralTableControl..ctor() +43
ASP.project_referral_TestPage_aspx.__BuildControlProjectReferralTableControl() in f:\Test\Test\Test Page\TestPage.aspx:542
ASP.project_referral_TestPage_aspx.__BuildControl__control27(Control __ctrl) in f:\Test\Test\Test Page\TestPage.aspx:539
System.Web.UI.CompiledTemplateBuilder.InstantiateIn(Control container) +12
System.Web.UI.UpdatePanel.CreateContents() +118
System.Web.UI.UpdatePanel.set_ContentTemplate(ITemplate value) +222
ASP.project_referral_TestPage_aspx.__BuildControlProjectReferralTableControlUpdatePanel() in f:\Test\Test\Test Page\TestPage.aspx:539
ASP.project_referral_TestPage_aspx.__BuildControlForm1() in f:\Test\Test\Test Page\TestPage.aspx:25
ASP.project_referral_TestPage_aspx.__BuildControlBody1() in f:\Test\Test\Test Page\TestPage.aspx:24
ASP.project_referral_TestPage_aspx.__BuildControlTree(Test_Test_TestPage_aspx __ctrl) in f:\Test\Test\Test Page\TestPage.aspx:1
ASP.project_referral_TestPage_aspx.FrameworkInitialize() in f:\Test\Test\Test Page\TestPage.aspx.cs:912308
System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +56
System.Web.UI.Page.ProcessRequest() +80
System.Web.UI.Page.ProcessRequestWithNoAssert(HttpContext context) +21
System.Web.UI.Page.ProcessRequest(HttpContext context) +49
ASP.project_referral_TestPage_aspx.ProcessRequest(HttpContext context) in c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\Test\964f5007\2c6ae9b9\App_Web_xmte9nts.0.cs:0
System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +181
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +75

Nish Nishant 24-Feb-11 11:15am

So doesn't it show the line in loadXML that throws the exception?

postonoh 24-Feb-11 11:20am

Line 981: obj.ReadStartElement("BusinessName", rows.SubConstructionManager1.Text);

Nish Nishant 24-Feb-11 12:41pm

It's most likely that rows.SubConstructionManager1 is null. So when you call Text on it, it will throw.

postonoh 24-Feb-11 13:53pm

Change code look like this now can see data from xml.

XmlDocument xmldoc = new XmlDocument();
xmldoc.Load(@"c:\temp\reg.xml");
XmlNodeList xmlnodelist = xmldoc.;
XmlNode xmlnode = xmldoc;
rows.SubConstructionManager1.Text = xmlnode["BusinessName"].InnerText;
rows.SubContactName1.Text = xmlnode["OwnerName"].InnerText;
rows.SubAddress1.Text = xmlnode["Address"].InnerText;
rows.SubCity1.Text = xmlnode["City"].InnerText;
rows.SubState1.Text = xmlnode["State"].InnerText;
rows.SubZip1.Text = xmlnode["ZipCode"].InnerText;
rows.SubPhone1.Text = xmlnode["Phone"].InnerText;
rows.SubFax1.Text = xmlnode["Fax"].InnerText;
rows.SubEmail1.Text = xmlnode["EmailAddress"].InnerText;

3 solutions

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Sergey Alexandrovich Kryukov · Accepted Answer · 2011-02-24T09:29:00

Solution 2

The whole approach is bad, because you make assumptions on XML contents. You also use hard-coded immediate string constants in you code, which is always bad, you should make it data-driven instead, for example you can use XSD as a source of valid elements.

So, instead of trying to read what you're expected, try to read all until you read the document to its end and try to match what you can see on the road. Start from the sample on this page: http://msdn.microsoft.com/en-us/library/system.xml.xmlreader.read.aspx[^].

—SA

Posted 24-Feb-11 9:29am

Sergey Alexandrovich Kryukov

Comments

postonoh 24-Feb-11 15:35pm

I tried something like this at first.

XmlTextReader obj = new XmlTextReader(@"c:\temp\reg.xml");
string sr= "";
while(obj.Read())

switch (obj.NodeType)
{
case XmlNodeType.Element:
sr = obj.Name;
break;
case XmlNodeType.Text:

//this.SubConstructionManagerLabel1.Text = obj.GetAttribute("BusinessName");
rows.SubConstructionManager1.Text = obj.GetAttribute("BusinessName");
//break;
rows.SubContactName1.Text = obj.GetAttribute("OwnerName");
//break;
rows.SubAddress1.Text = obj.GetAttribute("Address");
// break;
rows.SubCity1.Text = obj.GetAttribute("City");
//break;
rows.SubState1.Text = obj.GetAttribute("State");
// break;
rows.SubZip1.Text = obj.GetAttribute("ZipCode");
// break;
rows.SubPhone1.Text = obj.GetAttribute("Phone");
// break;
rows.SubFax1.Text = obj.GetAttribute("Fax");
//break;
rows.SubEmail1.Text = obj.GetAttribute("Email");
break;
}

postonoh 24-Feb-11 15:42pm

Also I have page that is data driven and user search for companies when he select which companies he/she wants it saves the selection to XML file. They want to be able to recall them later use this file to populate other pages at a different time.

Sergey Alexandrovich Kryukov 24-Feb-11 17:22pm

You're doing same thing, work based on assumption. Best it can come to is unsupportable code...
--SA

Espen Harlinn 24-Feb-11 16:52pm

My 5 - Good point, it would be better to create something that supports binding ...

Sergey Alexandrovich Kryukov 24-Feb-11 17:22pm

Thank you.
-SA

postonoh 24-Feb-11 22:25pm

thanks

postonoh 24-Feb-11 22:56pm

I really appreciation this information. I new to using XML so thanks. I learning and want to do it right the first time. So thanks I used the XSD to create my XML Schema. Thanks again.
I believe that everyone needs a mentor to lead them into to success!

Espen Harlinn · Accepted Answer · 2011-02-24T11:03:00

Solution 3

You could create an XML Schema[^] for your xml document - this wil also help to improve the integrity of your xml file.

Once you have a schema, you can use xsd[^] to create a dataset for your xml file.

Content can be loaded into the dataset using the DataSet.ReadXml[^].

Now that you have a dataset containing the data for your xml file, you can set up bindings between your dataset and the UI elements using the design features of Visual Studio.

Regards
Espen Harlinn

Posted 24-Feb-11 11:03am

Espen Harlinn

Comments

Sergey Alexandrovich Kryukov 24-Feb-11 17:20pm

Very good, 5.
--SA

Espen Harlinn 24-Feb-11 17:37pm

Thank you SAKryukov!

postonoh 24-Feb-11 22:56pm

I really appreciation this information. I new to using XML so thanks. I learning and want to do it right the first time. So thanks I used the XSD to create my XML Schema. Thanks again.
I believe that everyone needs a mentor to lead them into to success!

Sergey Alexandrovich Kryukov 25-Feb-11 0:38am

You're welcome.
Thank you for accepting my Answer.
And well... no, not everyone needs a mentor in fact. Yes, I'm sure.
--SA

Espen Harlinn 25-Feb-11 3:24am

Thanks Mo John!

Sandeep Mewara · Accepted Answer · 2011-02-24T05:54:00

Solution 1

Did you try to DEBUG and see what are the values around the lines?

Looks like this part has issues: rows.SubConstructionManager1.Text
Check if rows or rows.SubConstructionManager1 is not null

Posted 24-Feb-11 5:54am

Sandeep Mewara

Comments

postonoh 24-Feb-11 12:15pm

Yes it is null, I am trying to insert the data found in the xml document to the text boxes

Sandeep Mewara 24-Feb-11 12:18pm

And thats the reason of error. Now, you need to correct your code and make sure that the object is populated and has the data as desired.

postonoh 24-Feb-11 12:29pm

Thanks, I put this snippet of code out here so maybe someone can inform me what I am missing.
I will do some research on other forums.

Thanks for you insight,

Nish Nishant 24-Feb-11 12:42pm

Voted 5, proposed as answer.

Sergey Alexandrovich Kryukov 24-Feb-11 15:29pm

You are right, of cause, my 5, but the approach itself should be very different.
Please see my Answer.
--SA

Espen Harlinn 24-Feb-11 16:51pm

Nicely spotted, my 5