Can i use the same variables in several cases without writing them multiple times? e.g.
switch(a)
{
case 1:
ans = string.Format("someString {0}, {1}, {2}", var1, var2, var3);
case 2:
ans = string.Format("anotherString {0}, {1}, {2}", var1, var2, var3);
case 3:
ans = string.Format("thirdString {0}, {1}, {2}", var1, var2, var3);
}
can I write the variables var1, var2 and var3 in one place only? thanks.
So only the format is changing while you want to insert the same values in each?
Then only select the format in your switch and do the string.Format once after it.
string fmt="";
switch(a)
{
case 1:
fmt = "someString {0}, {1}, {2}";
case 2:
fmt = "anotherString {0}, {1}, {2}";
case 3:
fmt = "thirdString {0}, {1}, {2}";
}
ans = string.Format(fmt, var1, var2, var3);
fmt if the variable a is not 1, 2 or 3, and you cannot use variable that not initialized in C#. So, use default instead of case 3, or declare fmt like string fmt = null.
a will be 1, 2 or 3. So you can use default instead of case 3, too.I would wrtie a Dictionary<int,string> let code more clear. then just put once var1,var2,var3
Dictionary<int, string> dict = new Dictionary<int, string>();
dict.Add(1, "someString");
dict.Add(2, "anotherString");
dict.Add(3, "thirdString");
string result = string.Empty;
if (dict.ContainsKey(a))
result = string.Format("{0} {1}, {2}, {3}", dict[a], var1, var2, var3);
EDIT
thank for @mjwills suggest
TryGetValue would be faster than ContainsKey because ContainsKey need to do twice search getting the value, but TryGetValue just once
Dictionary<int, string> dict = new Dictionary<int, string>();
dict.Add(1, "someString");
dict.Add(2, "anotherString");
dict.Add(3, "thirdString");
string ans = string.Empty;
string key = string.Empty;
if (dict.TryGetValue(a, out key))
ans = string.Format("{0} {1}, {2}, {3}", key, var1, var2, var3);
var temp = string.Format(" {0}, {1}, {2}", var1, var2, var3);
switch (a)
{
case 1: ans = "someString" + temp; break;
case 2: ans = "anotherString" + temp; break;
case 3: ans = "thirdString" + temp; break;
}
Shorter and less readable alternative in Visual Studio 2015 or above:
if ((uint)--a < 3)
ans = $"{new[] { "someString", "anotherString", "thirdString" }[a]} {var1}, {var2}, {var3}";
