So I get back errors using this code:

using System;

using System.Windows.Forms;

namespace RaisingSalaryGUI

$\{$

public partial class Form$1$ : Form

$\{$

public Form$1()$

$\{$

InitializeComponent$()$;

$\}$

private partial void Button$1\_$click$($object sender$,$ EventArgs e$)$;

$\}$

namespace ProjectedRaisesGUI

$\{$

public class Form$1$ : Form

$\{$

private readonly Label lblCurrentSalary;

private readonly TextBox txtCurrentSalary;

private readonly Button btnCalculate;

private Label lblResult;

public Form$1()$

$\{$

lblCurrentSalary $=$ new Label$()$;

txtCurrentSalary $=$ new TextBox$()$;

btnCalculate $=$ new Button$()$;

lblResult $=$ new Label$()$;

lblCurrentSalary.Text $=$ "Current Salary";

lblCurrentSalary.Location $=$ new System.Drawing.Point$(10,20)$;

lblCurrentSalary.AutoSize $=$ true;

txtCurrentSalary.Location $=$ new System.Drawing.Point$(150,20)$;

txtCurrentSalary.Width $=100$;

btnCalculate.Text $=$ "Calculate";

btnCalculate.Location $=$ new System.Drawing.Point$(10,60)$;

btnCalculate.Click $+=$ new System.EventHandler$($BtnCalculate$\_$Click$)$;

lblResult.Location $=$ new System.Drawing.Point$(10,100)$;

lblResult.AutoSize $=$ true;

this.Controls.Add$($lblCurrentSalary$)$;

this.Controls.Add$($txtCurrentSalary$)$;

this.Controls.Add$($btnCalculate$)$;

this.Controls.Add$($lblResult$)$;

this.Text $=$ "Projected Salary Calculator";

this.StartPosition $=$ FormStartPosition.CenterScreen;

this.Size $=$ new System.Drawing.Size$(300,200)$;

$\}$

private void BtnCalculate$\_$Click$($object sender$,$ System.EventArgs e$)$

$\{$

try

$\{$

double currentSalary $=$ System.Convert.ToDouble$($txtCurrentSalary$.$Text$)$;

double increaseRate $=0\mathrm{.}04$;

double projectedSalary $=$ currentSalary $*(1+$ increaseRate$)$;

lblResult.Text $=$ $"New Salary $$\{$projectedSalary:F$2\}"$;

$\}$

catch $($System$.$FormatException$)$

$\{$

MessageBox.Show$("$Please enter a valid number for the salary.", "Input Error", MessageBoxButtons.OK$,$ MessageBoxIcon.Error$)$;

$\}$

$\}$

$[$System$.$STAThread$]$

static void Main$()$

$\{$

Application.EnableVisualStyles$()$;

Application.SetCompatibleTextRenderingDefault$($false$)$;

Application.Run$($new Form$1())$;

$\}$

$\}$

$\}$

$\}$

and these are the errors:

Severity Code Description Project File Line Suppression State

Error $($active$)$ CS$0017$ Program has more than one entry point defined. Compile with $/$main to specify the type that contains the entry point.

Severity Code Description Project File Line Suppression State

Error $($active$)$ CS$8795$ Partial method 'Form$1.$Button$1\_$click$($object$,$ EventArgs$)\text{'}$ must have an implementation part because it has accessibility modifiers.

Severity Code Description Project File Line Suppression State

Error $($active$)$ CS$8370$ Feature 'extended partial methods' is not available in C# $7\mathrm{.}3.$ Please use language version $9\mathrm{.}0$ or greater.

Severity Code Description Project File Line Suppression State

Error $($active$)$ CS$0762$ Cannot create delegate from method 'Form$1.$Button$1\_$click$($object$,$ EventArgs$)\text{'}$ because it is a partial method without an implementing declaration

It has to be in C#$.$