如何使用带有参数名称数组作为参数的string.format？

Question

I want to create string from variables based on format of another string. It passes only string names, not references. Ref is not working. What can i do?

var format = "city, post_code, street, building_number,name"
var city = model["City"];
var post_code = model["Post_Code"];
var street = model["Street"];
var building_number = model["Building_Number"];
var name = model["Name"];
var arguments = format.Split(",");
var s = String.Format("{0} {1} {2} {3} {4}", new object[] {  arguments[0],  arguments[1], arguments[2], arguments[3], arguments[4] });

Answer 1

You're trying to use strings as variable names. C# is not PHP.

What you actually want is string interpolation:

var s = $"{city}, {post_code}, {street}, {building_number}, {name}";

Now if you want this format string to be variable, see:

• Is there a "String.Format" that can accept named input parameters instead of index placeholders?
• Using variables inside strings
• What's a good way of doing string templating in .NET?

Answer 2

Not sure about the expected result/functionality here.

Is format a static Information or can it vary? I interpreted the question as the later is inteded. A (quite basic) solution could be:

    public void foo(DataRow model, String format = "city,post_code,street,building_number,name")
    {
        var arguments = format.Split(',');

        var val1 = model[arguments[0]];
        var val2 = model[arguments[1]];
        var val3 = model[arguments[2]];
        var val4 = model[arguments[3]];
        var val5 = model[arguments[4]];

        var s = $"{val1} {val2} {val3} {val4} {val5}";
    }

Answer 3

You are not using the String.Format correctly. Modify your code like this

var s = String.Format("{0} {1} {2} {3} {4}", arguments[0], arguments[1], arguments[2], arguments[3], arguments[4]);