Parameters
- sourceRegion
- The source text region.
- symbolIndex
- The first index of symbol, in source region, which should be added to new text region.
- symbolCount
- The count of symbols that should be added to new text region.
This constructor creates the new text region from symbols of the specified text region.
Target Platforms: .NET 10; .NET 9; .NET 8; .NET 7; .NET 6; .NET Framework 4.8, 4.7, 4.6, 4.5, 4.0, 3.5