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I am trying to change an existing attribute value of an XML Node that has child nodes. I am getting an exception when trying to do this. 

string specificOwnerPath = "Owners/Owner[@id='" + startingOwnerName + startingOwnerZipCode + "']";
XmlNode ownerID = doc.SelectSingleNode(specificOwnerPath);
ownerID.Attributes["id"].Value = ownerNameTextBox.Text + ownerZipCodeTextBox.Text;

The exception I am getting says 'Object reference not set to the instance of an object and is occurring at the final line of code shown above. Does anyone have any suggestions on what I am doing wrong?

John Saunders
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user1546315
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  • Almost all cases of NullReferenceException are the same. Please see "[What is a NullReferenceException in .NET?](http://stackoverflow.com/questions/4660142/what-is-a-nullreferenceexception-in-net)" for some hints. – John Saunders Nov 12 '12 at 18:49

2 Answers2

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Add a check

if (ownerID != null)

to before the last line. Most probably your XPath is not correct (or there simply isn't any matching element).

Knaģis
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-1

if (ownerID != null)

Xpath is not correct in last line

Rahul Jawa
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  • It is not useful to duplicate existing answers. Please only post an answer if you something new to add and can provide a detailed explanation of what that is and how it will specifically answer the question. – Peter Duniho Apr 25 '21 at 16:54