Can not run the code

[songyanglihua]

I download the code.
Open src with VS2019.
When I Run Code.
private static string GetValue(string key, string cfg)
{
// Find start of 'Key'
int i = cfg.IndexOf(key);
if (i >= 0)
{
i = cfg.IndexOf('=', i);
int z = cfg.IndexOf(Environment.NewLine, i + 1);

            // Get only 'Value' text
            return cfg.Substring(i + 1, z - i).Trim();
        }

        return null;
    }

It's wrong.why?I want to run code on my computer.what should i do?

[intolerance]

Need more clarification here on what the actual problem is.