值不能为null。参数名称：读取嵌入文件内容时出现流错误

Question

I am doing an application in c#.

I get the error:

Value cannot be null. Parameter name: stream while reading the contentxs of embedded file

in the code

Stream strm = Asm.GetManifestResourceStream(Asm.GetName().Name + "." + Name);

How to solve this error?

Answer 1

The prefix to embedded resources is not the assembly name, but rather: the default namespace specified on the project. Your best tactic, though, is to look at:

string[] names = Asm.GetManifestResourceNames();
foreach(var name in names) Debug.WriteLine(name);

and see what the names actually are, and tweak the prefix accordingly. You will get null if it is not a complete match.

Answer 2

What I found is as once I faced this problem after adding a text file or template file to read the email body and than reading the path to that template file using below syntax:

Assembly asm = Assembly.GetExecutingAssembly();
string assemblyName = asm.GetName().Name;
string emailTemplateName = xyz.tt;
emailTemplateName = assemblyName + "." +  emailTemplateName;
using (StreamReader reader = new StreamReader(asm.GetManifestResourceStream(emailTemplateName)))
{
body = reader.ReadToEnd();
}

The file by default gets added to project library with property "Build Action"= Content. I changed value from "Content" to "Embedded Resource" and everything worked good.