The sample demonstrates how to lock and unlock an excel workbook.

using System;

using Spire.Xls;

namespace CellProtection
{
    class Program
    {
        static void Main(string[] args)
        {
            Workbook workbook = new Workbook();

            //Initialize worksheet
            workbook.CreateEmptySheets(1);
            Worksheet sheet = workbook.Worksheets[0];

            //Set the password
            Console.Write("Please input password:");
            string str = Console.ReadLine();
            Console.ReadKey();

            //Protect cells
            sheet.Range["A1"].Text = "Locked";
            sheet.Range["B1"].Text = "Unlocked";

            sheet.Range["A1"].Style.Locked = true;
            sheet.Range["B1"].Style.Locked = false;

            //Protect workbook
            workbook.Protect(str);
            workbook.SaveToFile("Sample.xls");
            System.Diagnostics.Process.Start(workbook.FileName);
        }
    }
}

Imports Spire.Xls
Module Module1

    Sub Main()
    
        Dim workbook As Workbook = New Workbook()

        'Initialize worksheet
        workbook.CreateEmptySheets(1)
        Dim sheet As Worksheet = workbook.Worksheets(0)

        'Protect workshet
        Console.Write("Please input password:")
        Dim str As String = Console.ReadLine()
        Console.ReadKey()

        sheet.Protect(str)

        'Protect cells
        sheet.Range("A1").Text = "Locked"
        sheet.Range("B1").Text = "Unlocked"

        sheet.Range("A1").Style.Locked = True
        sheet.Range("B1").Style.Locked = False

        'Protect workbook
        workbook.Protect(str)

        workbook.SaveToFile("Sample.xls")
        System.Diagnostics.Process.Start(workbook.FileName)
    End Sub
End Module

		private void btnRun_Click(object sender, System.EventArgs e)
		{
			Workbook workbook = new Workbook();
			
			//Initialize worksheet
			workbook.LoadFromFile(@"..\..\..\..\..\Data\VBASample.xls");
			Worksheet sheet = workbook.Worksheets[0];

			//Writes new sheet name
			sheet.Range["A1"].Text = this.textBox1.Text;

			workbook.SaveToFile("Sample.xls");
			ExcelDocViewer(workbook.FileName);
		}

		private void ExcelDocViewer( string fileName )
		{
			try
			{
				System.Diagnostics.Process.Start(fileName);
			}
			catch{}
		}

		Private Sub btnRun_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnRun.Click
			Dim workbook As Workbook = New Workbook()

			'Initialize worksheet
			workbook.LoadFromFile("..\..\..\..\..\Data\VBASample.xls")
			Dim sheet As Worksheet = workbook.Worksheets(0)

			'Writes new sheet name
			sheet.Range("A1").Text = Me.textBox1.Text

			workbook.SaveToFile("Sample.xls")
			ExcelDocViewer(workbook.FileName)
		End Sub

		Private Sub ExcelDocViewer(ByVal fileName As String)
			Try
				System.Diagnostics.Process.Start(fileName)
			Catch
			End Try
		End Sub

		private void btnRun_Click(object sender, System.EventArgs e)
		{
			Workbook workbook = new Workbook();
			
			//Initialize worksheet
			workbook.CreateEmptySheets(1);
			Worksheet sheet = workbook.Worksheets[0];
			sheet.GridLinesVisible = false;

			//Writes sample data
			CreateSampleData(sheet);

			//Sets page setup properties
			sheet.PageSetup.Orientation = PageOrientationType.Landscape;
			sheet.PageSetup.PaperSize = PaperSizeType.PaperA3;

			//Sets page break
			sheet.VPageBreaks.Add(sheet.Range["A5"]);
			sheet.HPageBreaks.Add(sheet.Range["C6"]);

			workbook.SaveToFile("Sample.xls");
			ExcelDocViewer(workbook.FileName);
		}

		private void CreateSampleData(Worksheet sheet)
		{
			//Country
			sheet.Range["A1"].Value = "Country";
			sheet.Range["A2"].Value = "Cuba";
			sheet.Range["A3"].Value = "Mexico";
			sheet.Range["A4"].Value = "France";
			sheet.Range["A5"].Value = "German";

			//Jun
			sheet.Range["B1"].Value = "Jun";
			sheet.Range["B2"].NumberValue = 6000;
			sheet.Range["B3"].NumberValue = 8000;
			sheet.Range["B4"].NumberValue = 9000;
			sheet.Range["B5"].NumberValue = 8500;

			//Aug
			sheet.Range["C1"].Value = "Aug";
			sheet.Range["C2"].NumberValue = 3000;
			sheet.Range["C3"].NumberValue = 2000;
			sheet.Range["C4"].NumberValue = 2300;
			sheet.Range["C5"].NumberValue = 4200;

			//Style
			sheet.Range["A1:C1"].Style.Font.IsBold = true;
			sheet.Range["A2:C2"].Style.KnownColor = ExcelColors.LightYellow;
			sheet.Range["A3:C3"].Style.KnownColor = ExcelColors.LightGreen1;
			sheet.Range["A4:C4"].Style.KnownColor = ExcelColors.LightOrange;
			sheet.Range["A5:C5"].Style.KnownColor = ExcelColors.LightTurquoise;

			//Border
			sheet.Range["A1:C5"].Style.Borders[BordersLineType.EdgeTop].Color = Color.FromArgb(0, 0, 128);
			sheet.Range["A1:C5"].Style.Borders[BordersLineType.EdgeTop].LineStyle = LineStyleType.Thin;
			sheet.Range["A1:C5"].Style.Borders[BordersLineType.EdgeBottom].Color = Color.FromArgb(0, 0, 128);
			sheet.Range["A1:C5"].Style.Borders[BordersLineType.EdgeBottom].LineStyle = LineStyleType.Thin;
			sheet.Range["A1:C5"].Style.Borders[BordersLineType.EdgeLeft].Color = Color.FromArgb(0, 0, 128);
			sheet.Range["A1:C5"].Style.Borders[BordersLineType.EdgeLeft].LineStyle = LineStyleType.Thin;
			sheet.Range["A1:C5"].Style.Borders[BordersLineType.EdgeRight].Color = Color.FromArgb(0, 0, 128);
			sheet.Range["A1:C5"].Style.Borders[BordersLineType.EdgeRight].LineStyle = LineStyleType.Thin;

			sheet.Range["B2:C5"].Style.NumberFormat = "\"$\"#,##0";
		}

		private void ExcelDocViewer( string fileName )
		{
			try
			{
				System.Diagnostics.Process.Start(fileName);
			}
			catch{}
		}

		Private Sub btnRun_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnRun.Click
			Dim workbook As Workbook = New Workbook()

			'Initialize worksheet
			workbook.CreateEmptySheets(1)
			Dim sheet As Worksheet = workbook.Worksheets(0)
			sheet.GridLinesVisible = False

			'Writes sample data
			CreateSampleData(sheet)

			'Sets page setup properties
			sheet.PageSetup.Orientation = PageOrientationType.Landscape
			sheet.PageSetup.PaperSize = PaperSizeType.PaperA3

			'Sets page break
			sheet.VPageBreaks.Add(sheet.Range("A5"))
			sheet.HPageBreaks.Add(sheet.Range("C6"))

			workbook.SaveToFile("Sample.xls")
			ExcelDocViewer(workbook.FileName)
		End Sub

		Private Sub CreateSampleData(ByVal sheet As Worksheet)
			'Country
			sheet.Range("A1").Value = "Country"
			sheet.Range("A2").Value = "Cuba"
			sheet.Range("A3").Value = "Mexico"
			sheet.Range("A4").Value = "France"
			sheet.Range("A5").Value = "German"

			'Jun
			sheet.Range("B1").Value = "Jun"
			sheet.Range("B2").NumberValue = 6000
			sheet.Range("B3").NumberValue = 8000
			sheet.Range("B4").NumberValue = 9000
			sheet.Range("B5").NumberValue = 8500

			'Aug
			sheet.Range("C1").Value = "Aug"
			sheet.Range("C2").NumberValue = 3000
			sheet.Range("C3").NumberValue = 2000
			sheet.Range("C4").NumberValue = 2300
			sheet.Range("C5").NumberValue = 4200

			'Style
			sheet.Range("A1:C1").Style.Font.IsBold = True
			sheet.Range("A2:C2").Style.KnownColor = ExcelColors.LightYellow
			sheet.Range("A3:C3").Style.KnownColor = ExcelColors.LightGreen1
			sheet.Range("A4:C4").Style.KnownColor = ExcelColors.LightOrange
			sheet.Range("A5:C5").Style.KnownColor = ExcelColors.LightTurquoise

			'Border
			sheet.Range("A1:C5").Style.Borders(BordersLineType.EdgeTop).Color = Color.FromArgb(0, 0, 128)
			sheet.Range("A1:C5").Style.Borders(BordersLineType.EdgeTop).LineStyle = LineStyleType.Thin
			sheet.Range("A1:C5").Style.Borders(BordersLineType.EdgeBottom).Color = Color.FromArgb(0, 0, 128)
			sheet.Range("A1:C5").Style.Borders(BordersLineType.EdgeBottom).LineStyle = LineStyleType.Thin
			sheet.Range("A1:C5").Style.Borders(BordersLineType.EdgeLeft).Color = Color.FromArgb(0, 0, 128)
			sheet.Range("A1:C5").Style.Borders(BordersLineType.EdgeLeft).LineStyle = LineStyleType.Thin
			sheet.Range("A1:C5").Style.Borders(BordersLineType.EdgeRight).Color = Color.FromArgb(0, 0, 128)
			sheet.Range("A1:C5").Style.Borders(BordersLineType.EdgeRight).LineStyle = LineStyleType.Thin

			sheet.Range("B2:C5").Style.NumberFormat = """$""#,##0"
		End Sub

		Private Sub ExcelDocViewer(ByVal fileName As String)
			Try
				System.Diagnostics.Process.Start(fileName)
			Catch
			End Try
		End Sub