“String Does Not Contain Definition For Value”

Question

I am extracting the value in the app.config for the key of keyUri and see this syntax used by MS , as well as having used this syntax as well when doing connection strings. In the below snippet ( System.Configuration has been added, and the DLL has been added) of C#, I am getting this error:

C#

/// Error on the .Value
string keyUri = ConfigurationManager.AppSettings["keyUri"].Value;

app.config

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <startup>
    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
  </startup>
  <appSettings>
    <add key="keyUri" value="test" />
  </appSettings>
</configuration>

Based on the code, it should be looking within the <appSettings> , and returning the value for the key keyUri . Instead, I get an error stating,

"String Does Not Contain Definition For Value"

Answer 1

The ConfigurationManager.AppSettings stores the data as KeyValuePair, so by specifying the key you will get the value. SO its fine to use like this:

string keyUri = ConfigurationManager.AppSettings["keyUri"]

Which means ConfigurationManager.AppSettings["keyUri"] will return a string, when you append the .Value to this line, you are asking the compiler to get the value property of the string, hence it says "String Does Not Contain Definition For Value" . By using the above code you will get the required value in the string variable keyUri .

Answer 2

string keyUri = ConfigurationManager.AppSettings["keyUri"];

这会给你结果

Answer 3

ConfigurationManager.AppSettings is a NameValueCollection . When you access it using the index , it returns a string . string doesn't have a property Value , in this case the returned string is the value.

So simply omit .Value :

string keyUri = ConfigurationManager.AppSettings["keyUri"];

Answer 4

It's Obvious that there is no property Value as other have already mentioned. So you should access it like

 string keyUri = ConfigurationManager.AppSettings["keyUri"];

But I think you meant to call the GetValues() method like below cause ConfigurationManager.AppSettings returns a NameValueCollection

string keyUri = ConfigurationManager.AppSettings.GetValues("keyUri");