How to Convert and Parse Different Data Types in C#

When you declare a new variable in C#, you’ll usually initialize it with a particular data type. This might be an integer, decimal, boolean, string, or another data type.

You can convert a value from one data type to another. For example, if you are converting a string to an integer, you’ll need to parse the value first. Here are a few different ways you can convert and parse values.

Why Do You Need to Convert or Parse Data?

An example of when you may need to parse data is if you’re requesting user input in a C# console application:

Console.WriteLine("Enter your age:");
string salary = Console.ReadLine();

In this case, the user will enter an integer value, but the application will store it as a string by default. If you tried to use the string value in any calculations, you’d get a compilation error:

Another reason to convert data types is to access certain methods that are only available for a specific data type. For example, the DateTime struct contains a function that allows you to add minutes. If you were using a string instead, you would not have access to the method:

You may also want to convert a value to another data type if you needed to follow the data type structure of a class created in C# or a structure in C#.

How to Convert and Parse Different Data Types

You can parse different data types such as integers, doubles, boolean types, and datetime types.

Strings to Integers

To convert a string to an integer, use the Parse() method:

string strInt = "45";
int int32 = Int32.Parse(strInt);
Console.WriteLine(int32);

You can also parse the string into integers of different bit sizes, such as Int16, Int32, or Int64.

int int16 = Int16.Parse(strInt);
Console.WriteLine(int16);

If you are using the Parse() method, make sure the string value represents an integer. If you try to parse a non-integer value such as “Hello”, you will receive a parsing error at runtime.

string invalidString = "Hello";
int invalidResult = Int32.Parse(invalidString);

You can also use the TryParse() method to catch any exceptions that could occur when parsing:

int tryParseResult = 0;

if (Int32.TryParse(invalidString, out tryParseResult))
{
Console.WriteLine(tryParseResult);
}
else
{
Console.WriteLine("Something went wrong");
}

To convert an integer back to a string, use the ToString() method:

string intString = 45.ToString();
Console.WriteLine(intString);

Strings to Doubles

Parsing a string to a double is very similar to parsing one to an integer. Use the Parse() method from the Double class:

string strDouble = "90.5";
double d = Double.Parse(strDouble);
Console.WriteLine(d);

As with integers, you can also use the TryParse() method to catch any parsing errors that could occur:

string invalidStringDouble = "Hello";
double tryParseDouble = 0;

if (Double.TryParse(invalidStringDouble, out tryParseDouble))
{
Console.WriteLine(tryParseDouble);
}

To convert a double back to an integer, use the ToString() method:

double dDouble = 90.5;
string dString = dDouble.ToString();
Console.WriteLine(dString);

Doubles to Integers

You can use casting to convert a double to an integer. Because an integer only stores a whole number, the conversion will remove the decimal places. For example, converting “12.34” will only store the value “12”.

double dValue = 12.34;
int iValue = (int)dValue;
Console.WriteLine(iValue);

You can also cast an integer back to a double:

dValue = (double)iValue;
Console.WriteLine(dValue);

Strings and Boolean Values

To convert a string to a boolean, use either the Parse() or ToBoolean() method:

string stringBool = "True";
bool b = bool.Parse(stringBool);

b = Convert.ToBoolean(stringBool);
Console.WriteLine(b);

To convert a boolean back to a string, Use the ToString() method:

string strTrue = true.ToString();
string strFalse = false.ToString();

Integers and Boolean Values

To convert an integer to a boolean, use the ToBoolean() method to convert either a “1” or “0” to its equivalent boolean value. The value “1” will convert to “true” while “0” converts to “false”:

int falseBit = 0;
int trueBit = 1;
Console.WriteLine(Convert.ToBoolean(falseBit));
Console.WriteLine(Convert.ToBoolean(trueBit));

You can also pass an integer value other than “1” or “0” to the ToBoolean() method. By default, the method will still return “true”:

int invalidBit = 8;
Console.WriteLine(Convert.ToBoolean(invalidBit));

To convert a boolean back to an integer, use the Convert.ToInt32() method. Converting “true” will return a “1”, and converting “false” will return a “0”.

bool iBool = true;
int bInt = Convert.ToInt32(iBool);
Console.WriteLine(bInt);

Strings to DateTime

To parse a string to datetime format, use the DateTime.Parse() method:

DateTime newDateTime = DateTime.Parse("01/01/2018 00:00:00");
Console.WriteLine(newDateTime);

To convert a datetime back to a string, use the ToString() method:

DateTime dt = new DateTime(2018, 1, 1);
string dtString = dt.ToString();
Console.WriteLine(dtString);

Parsing Values to Different Data Types

Now you understand how to convert values from one data type to another. These are not the only conversions out there, so feel free to learn more about other data types in C#.

You can also explore how other data types work in other languages, such as JavaScript.