StringBuilder.Append Method (String, Int32, Int32)

May 11, 2014

Appends a copy of a specified substring to the end of this instance.

Namespace:  System.Text
Assembly:  mscorlib (in mscorlib.dll)

public StringBuilder Append(
	string value,
	int startIndex,
	int count
)

Parameters

value
Type: System.String
The String that contains the substring to append.
startIndex
Type: System.Int32
The starting position of the substring within value.
count
Type: System.Int32
The number of characters in value to append.

Return Value

Type: System.Text.StringBuilder
A reference to this instance after the append operation has completed.

ExceptionCondition
ArgumentNullException

value is null, and startIndex and count are not zero.

ArgumentOutOfRangeException

count less than zero.

-or-

startIndex less than zero.

-or-

startIndex + count is greater than the length of value.

-or-

Enlarging the value of this instance would exceed its maximum capacity.

This method appends the specified range of characters in value to the current instance. If value is null and startIndex and count are both zero, no changes are made.

The Append method modifies the existing instance of this class; it does not return a new class instance. Because of this, you can call a method or property on the existing reference and you do not have to assign the return value to a StringBuilder object, as the following example illustrates.


string str = "First;George Washington;1789;1797";
int index = 0;
System.Text.StringBuilder sb = new System.Text.StringBuilder();
int length = str.IndexOf(';', index);      
sb.Append(str, index, length).Append(" President of the United States: ");
index += length + 1;
length = str.IndexOf(';', index) - index;
sb.Append(str, index, length).Append(", from ");
index += length + 1;
length = str.IndexOf(';', index) - index;
sb.Append(str, index, length).Append(" to ");
index += length + 1;
sb.Append(str, index, str.Length - index);
outputBlock.Text += sb + Environment.NewLine;
// The example displays the following output:
//    First President of the United States: George Washington, from 1789 to 1797      


The capacity of this instance is adjusted as needed.

Windows Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Windows Phone

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