C# | Convert.ToBase64String() Method | Set-1
Last Updated :
11 Jul, 2025
Convert.ToBase64String() Method is used to convert the value of an array of 8-bit unsigned integers to its equivalent string representation which is encoded with base-64 digits. There are 4 methods in the overload of this method which are as follows:
- ToBase64String(Byte[], Int32, Int32) Method
- ToBase64String(Byte[], Int32, Int32, Base64FormattingOptions) Method
- ToBase64String(Byte[], Base64FormattingOptions) Method
- ToBase64String(Byte[]) Method
Here, we will discuss only the
first method.
ToBase64String(Byte[], Int32, Int32) Method is used to convert a subset of an array of 8-bit unsigned integers to its equivalent string representation which is encoded with base-64 digits. Parameters specify the subset as an offset in the input array, and the number of elements in the array to convert.
Syntax:
public static string ToBase64String (byte[] inArray, int offset, int length);
Parameters:
- inArray: It is an array of 8-bit unsigned integers.
- offset: It is an offset in inArray.
- length: It is the number of elements of inArray to convert.
Return Value: This method returns the string representation in base 64 of length elements of
inArray, starting at position offset.
Exceptions:
- ArgumentNullException: If inArray is null.
- ArgumentOutOfRangeException: If the offset or length is negative OR offset plus length is greater than the length of inArray.
Below programs illustrate the use of
Convert.ToBase64String(Byte[], Int32, Int32) Method:
Example 1:
csharp
// C# program to demonstrate the
// Convert.ToBase64String() Method
using System;
class GFG {
// Main Method
public static void Main()
{
try {
// defining and initializing
// byte1 and byte2
byte[] byte1 = {2, 4, 6, 8, 10,
12, 14, 16, 18, 20};
byte[] byte2 = {10, 20, 30, 40, 50};
// calling get() Method
get(byte1, "byte1");
Console.WriteLine("");
get(byte2, "byte2");
}
catch (ArgumentNullException e) {
Console.Write("Exception Thrown: ");
Console.Write("{0}", e.GetType(), e.Message);
}
catch (ArgumentOutOfRangeException e) {
Console.Write("Exception Thrown: ");
Console.Write("{0}", e.GetType(),
e.Message);
}
}
// Defining get() method
public static void get(byte[] bytes, string str)
{
Console.WriteLine("For {0}", str);
// converting byte to base 64 string
string val = Convert.ToBase64String(bytes,
0, bytes.Length);
// display the converted string
Console.WriteLine("converted string: {0}", val);
}
}
Output:
For byte1
converted string: AgQGCAoMDhASFA==
For byte2
converted string: ChQeKDI=
Example 2: For
ArgumentNullException
csharp
// C# program to demonstrate the
// Convert.ToBase64String() Method
using System;
class GFG {
// Main Method
public static void Main()
{
try {
// defining and initializing
// byte1
byte[] byte1 = {2, 4, 6, 8, 10,
12, 14, 16, 18, 20};
// calling get() Method
get(byte1, "byte1");
Console.WriteLine("");
// converting base 64 string
// to byte array
Console.WriteLine("bye array is null");
string val = Convert.ToBase64String(null, 0, 10);
Console.WriteLine("Converted byte value: {0}", val);
}
catch (ArgumentNullException e) {
Console.Write("Exception Thrown: ");
Console.Write("{0}", e.GetType(), e.Message);
}
catch (ArgumentOutOfRangeException e) {
Console.Write("Exception Thrown: ");
Console.Write("{0}", e.GetType(),
e.Message);
}
}
// Defining get() method
public static void get(byte[] bytes, string str)
{
Console.WriteLine("For {0}", str);
// converting byte to base 64 string
string val = Convert.ToBase64String(bytes,
0, bytes.Length);
// display the converted string
Console.WriteLine("converted string: {0}", val);
}
}
Output:
For byte1
converted string: AgQGCAoMDhASFA==
bye array is null
Exception Thrown: System.ArgumentNullException
Example 3: For
ArgumentOutOfRangeException
csharp
// C# program to demonstrate the
// Convert.ToBase64String() Method
using System;
class GFG {
// Main Method
public static void Main()
{
try {
// defining and initializing
// byte1
byte[] byte1 = {2, 4, 6, 8, 10,
12, 14, 16, 18, 20};
// calling get() Method
get(byte1, "byte1");
Console.WriteLine("");
// converting base 64 string to byte array
Console.WriteLine("Length is negative");
string val = Convert.ToBase64String(byte1, 0, -10);
Console.WriteLine("Converted byte value: {0}", val);
}
catch (ArgumentNullException e) {
Console.Write("Exception Thrown: ");
Console.Write("{0}", e.GetType(), e.Message);
}
catch (ArgumentOutOfRangeException e) {
Console.Write("Exception Thrown: ");
Console.Write("{0}", e.GetType(),
e.Message);
}
}
// Defining get() method
public static void get(byte[] bytes, string str)
{
Console.WriteLine("For {0}", str);
// converting byte to base 64 string
string val = Convert.ToBase64String(bytes,
0, bytes.Length);
// display the converted string
Console.WriteLine("converted string: {0}", val);
}
}
Output:
For byte1
converted string: AgQGCAoMDhASFA==
Length is negative
Exception Thrown: System.ArgumentOutOfRangeException
Reference:
