String Conversion
SemVer provides bidirectional implicit conversions with string, and a deterministic ToString() implementation.
Read this page when you pass versions to or from string-based APIs.
ToString()
Returns the canonical SemVer 2.0.0 string representation of the version.
The output format is:
MAJOR.MINOR.PATCH[-PRERELEASE][+METADATA]
Pre-release and metadata segments are included only when they are non-null.
SemVer.Parse("1.2.3").ToString(); // "1.2.3"
SemVer.Parse("1.2.3-alpha").ToString(); // "1.2.3-alpha"
SemVer.Parse("1.2.3+build.1").ToString(); // "1.2.3+build.1"
SemVer.Parse("1.2.3-alpha+build.1").ToString(); // "1.2.3-alpha+build.1"
ToString() is the inverse of Parse — a round-trip through Parse → ToString always returns the original string.
Implicit conversion from string
Assigning a string literal (or variable) to a SemVer variable calls Parse implicitly:
SemVer version = "1.2.3-rc.1";
This is equivalent to:
SemVer version = SemVer.Parse("1.2.3-rc.1");
Warning
The implicit conversion uses the throwing Parse path. An invalid string will throw ArgumentException. Use TryParse if the input may be untrusted.
Practical uses
// Method parameters
void SetMinVersion(SemVer min) { /* ... */ }
SetMinVersion("2.0.0"); // works
// Collections
var allowed = new HashSet<SemVer> { "1.0.0", "1.1.0", "2.0.0" };
// Comparison operators with literals
SemVer current = SemVer.Parse("1.5.0");
bool tooOld = current < "2.0.0"; // true
Implicit conversion to string
Assigning a SemVer to a string variable calls ToString() implicitly:
SemVer version = SemVer.Parse("1.2.3-alpha+build.1");
string text = version; // "1.2.3-alpha+build.1"
This is equivalent to:
string text = version.ToString();
Practical uses
// Storing in a string field
string currentVersion = SemVer.Parse("3.0.0");
// Passing to string-accepting APIs
Console.WriteLine(SemVer.Parse("1.0.0")); // ToString() called automatically
File.WriteAllText("version.txt", SemVer.Parse("1.0.0")); // implicit to string
Prefix
The Prefix property returns only the MAJOR.MINOR.PATCH part, omitting any pre-release or metadata:
SemVer.Parse("1.2.3-alpha+build.1").Prefix; // "1.2.3"
SemVer.Parse("1.2.3").Prefix; // "1.2.3"
Useful when you need to compare or display only the numeric version core.