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TextBoxBase::GetFirstCharIndexFromLine Method

Retrieves the index of the first character of a given line.

Namespace:  System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

int GetFirstCharIndexFromLine(
	int lineNumber


Type: System::Int32
The line for which to get the index of its first character.

Return Value

Type: System::Int32
The zero-based index of the first character in the specified line.


The value of the lineNumber parameter is less than zero.

Line numbering in the text box starts at zero. If the lineNumber parameter is greater than the last line in the text box, GetFirstCharIndexFromLine returns -1.

GetFirstCharIndexFromLine returns the first character index of a physical line. The physical line is the displayed line, not the assigned line. The number of displayed lines can be greater than the number of assigned lines due to word wrap. For example, if you assign two long lines to a RichTextBox control and set Multiline and WordWrap to true, the two long assigned lines result in four physical (or displayed lines).

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.