Save (Insert) dynamic ASP.Net GridView checked (selected) rows to database using C#

How to insert dynamic GridView selected rows to database.

using System;
using System.Data;
using System.Data.SqlClient;
using System.Web.UI.WebControls;
using System.Configuration;


namespace ReceiptEntry
{
    public partial class ReceiptEntry : System.Web.UI.Page
    {
        private readonly string connectionString = ConfigurationManager.ConnectionStrings["ReceiptEntryDB"].ConnectionString;

        protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                // Bind the CheckBoxList with fee headers from the database
                if (chkFeesHeader.Items.Count == 0)
                {
                    BindFeeHeaders();
                }
            }
        }

        protected void btnSave_Click(object sender, EventArgs e)
        {
            int rollNo;
            if (!int.TryParse(txtRollNo.Text, out rollNo))
            {
                return;
            }

            string name = txtName.Text;
            string department = txtDepartment.Text;

            int batchYear;
            if (!int.TryParse(txtBatchYear.Text, out batchYear))
            {
                return;
            }

            InsertStudentData(rollNo, name, department, batchYear);

            foreach (ListItem item in chkFeesHeader.Items)
            {
                if (item.Selected)
                {
                    string feeHeader = item.Text;
                    int feeAmount = GetFeeAmountFromDatabase(feeHeader);
                    InsertFeeData(rollNo, feeHeader, feeAmount);
                }
            }
            {

                GridView1.DataBind();

            }

        }
        protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
        {
            int feeID = Convert.ToInt32(GridView1.DataKeys[e.RowIndex].Value);
            TextBox txtPaidAmount = (TextBox)GridView1.Rows[e.RowIndex].FindControl("txtFees");
            int paidAmount = Convert.ToInt32(txtPaidAmount.Text);

            UpdatePaidAmount(feeID, paidAmount);

            GridView1.DataBind();
        }
        private void BindFeeHeaders()
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                connection.Open();
                using (SqlCommand cmd = new SqlCommand("SELECT FeeHeader FROM tbl_FeeHeaders", connection))
                {
                    using (SqlDataReader reader = cmd.ExecuteReader())
                    {
                        while (reader.Read())
                        {
                            ListItem item = new ListItem(reader["FeeHeader"].ToString());
                            chkFeesHeader.Items.Add(item);
                        }
                    }
                }
            }
        }

        private void InsertStudentData(int rollNo, string name, string department, int batchYear)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                connection.Open();
                using (SqlCommand cmd = new SqlCommand("sp_InsertStudent", connection))
                {
                    cmd.CommandType = CommandType.StoredProcedure;
                    cmd.Parameters.AddWithValue("@RollNo", rollNo);
                    cmd.Parameters.AddWithValue("@Name", name);
                    cmd.Parameters.AddWithValue("@Department", department);
                    cmd.Parameters.AddWithValue("@BatchYear", batchYear);
                    cmd.ExecuteNonQuery();
                }
            }
        }
        private void InsertFeeData(int rollNo, string feeHeader, int feeAmount)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                connection.Open();
                using (SqlCommand cmd = new SqlCommand("sp_InsertFee", connection))
                {
                    cmd.CommandType = CommandType.StoredProcedure;
                    cmd.Parameters.AddWithValue("@RollNo", rollNo);
                    cmd.Parameters.AddWithValue("@FeeHeader", feeHeader);
                    cmd.Parameters.AddWithValue("@FeeAmount", feeAmount);
                    cmd.ExecuteNonQuery();
                }
            }
        }
                private void UpdatePaidAmount(int feeID, int paidAmount)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                connection.Open();
                using (SqlCommand cmd = new SqlCommand("sp_UpdateFee", connection))
                {
                    cmd.CommandType = CommandType.StoredProcedure;
                    cmd.Parameters.AddWithValue("@FeeID", feeID);
                    cmd.Parameters.AddWithValue("@PaidAmount", paidAmount);
                    cmd.ExecuteNonQuery();
                }
            }
        }
          private int GetFeeAmountFromDatabase(string feeHeader)
          {
            int feeAmount = 0; // Initialize with 0
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                connection.Open();
                using (SqlCommand cmd = new SqlCommand("SELECT FeeAmount FROM tbl_FeeHeaders WHERE FeeHeader = @FeeHeader", connection))
                {
                    cmd.Parameters.AddWithValue("@FeeHeader", feeHeader);
                    using (SqlDataReader reader = cmd.ExecuteReader())
                    {
                        if (reader.Read())
                        {
                            feeAmount = Convert.ToInt32(reader["FeeAmount"]);
                        }
                    }
                }
            }
            return feeAmount;
          }
    }
}

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="ReceiptEntry.aspx.cs" Inherits="ReceiptEntry.ReceiptEntry" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>Receipt Entry</title>
</head>
<body>
    <form id="form1" runat="server">
        <div>
            <!-- Student Information -->
            <label>Roll No:</label>
            <asp:TextBox ID="txtRollNo" runat="server"></asp:TextBox><br />
            <label>Name:</label>
            <asp:TextBox ID="txtName" runat="server"></asp:TextBox><br />
            <label>Department:</label>
            <asp:TextBox ID="txtDepartment" runat="server"></asp:TextBox><br />
            <label>Batch Year:</label>
            <asp:TextBox ID="txtBatchYear" runat="server"></asp:TextBox><br />

            <!-- Fee Headers -->
            <label>Fees Header:</label>
            <asp:CheckBoxList ID="chkFeesHeader" runat="server" RepeatDirection="Horizontal">
                <asp:ListItem>Admission</asp:ListItem>
                <asp:ListItem>Tuition</asp:ListItem>
                <asp:ListItem>Others</asp:ListItem>
            </asp:CheckBoxList><br />

            <!-- Save Button -->
            <asp:Button ID="btnSave" runat="server" Text="Save" OnClick="btnSave_Click" /><br />

            <!-- GridView to display fee data -->
            <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false" DataKeyNames="FeeID"
                          OnRowUpdating="GridView1_RowUpdating">
                <Columns>
                    <asp:BoundField DataField="SNO" HeaderText="S NO" />
                    <asp:BoundField DataField="Select" HeaderText="Select" />
                    <asp:BoundField DataField="FeeHeader" HeaderText="Fees Header" />
                    <asp:TemplateField HeaderText="Fees">
                        <ItemTemplate>
                            <asp:TextBox ID="txtFees" runat="server" Text='<%# Bind("FeeAmount") %>'></asp:TextBox>
                        </ItemTemplate>
                    </asp:TemplateField>
                    <asp:TemplateField HeaderText="Paid">
                        <ItemTemplate>
                            <asp:Label ID="lblPaid" runat="server" Text='<%# Bind("PaidAmount") %>'></asp:Label>
                        </ItemTemplate>
                    </asp:TemplateField>
                    <asp:TemplateField HeaderText="Balance">
                        <ItemTemplate>
                            <asp:Label ID="lblBalance" runat="server" Text='<%# Eval("Balance") %>'></asp:Label>
                        </ItemTemplate>
                    </asp:TemplateField>
                    <asp:TemplateField HeaderText="To Be Paid">
                        <ItemTemplate>
                            <asp:TextBox ID="txtToBePaid" runat="server" Text='<%# Bind("ToBePaid") %>'></asp:TextBox>
                        </ItemTemplate>
                    </asp:TemplateField>
                </Columns>
            </asp:GridView>
        </div>
    </form>
</body>
</html>

CREATE TABLE tbl_Students (
 RollNo INT PRIMARY KEY,
 Name NVARCHAR(255),
 Department NVARCHAR(255),
 BatchYear INT
);



CREATE TABLE tbl_Fees (
 FeeID INT PRIMARY KEY IDENTITY(1,1),
 RollNo INT,
 FeeHeader NVARCHAR(255),
 FeeAmount INT,
 PaidAmount INT,
 CONSTRAINT FK_Student FOREIGN KEY (RollNo) REFERENCES tbl_Students(RollNo)
);

-----------------------------------

CREATE PROCEDURE sp_InsertFee
 @RollNo INT,
 @FeeHeader NVARCHAR(255),
 @FeeAmount INT,
 @PaidAmount INT
AS
BEGIN
 INSERT INTO tbl_Fees (RollNo, FeeHeader, FeeAmount, PaidAmount)
 VALUES (@RollNo, @FeeHeader, @FeeAmount, @PaidAmount)
END;

----------------

CREATE PROCEDURE sp_UpdateFee
 @FeeID INT,
 @PaidAmount INT,
 @FeeAmount INT
AS
BEGIN
 
 UPDATE tbl_Fees
 SET PaidAmount = @PaidAmount,
 FeeAmount = @FeeAmount
 WHERE FeeID = @FeeID;
END;

CREATE PROCEDURE sp_InsertStudent
 @RollNo INT,
 @Name NVARCHAR(255),
 @Department NVARCHAR(255),
 @BatchYear INT
AS
BEGIN
 INSERT INTO tbl_Students (RollNo, Name, Department, BatchYear)
 VALUES (@RollNo, @Name, @Department, @BatchYear);
END;
---------------------

CREATE TABLE tbl_FeeHeaders
(
 FeeHeaderID INT PRIMARY KEY IDENTITY(1,1),
 FeeHeader NVARCHAR(255) NOT NULL,
 FeeAmount INT NOT NULL
);


INSERT INTO tbl_FeeHeaders (FeeHeader, FeeAmount)
VALUES
 ('Admission', 1000),
 ('Tuition', 2000),
 ('Others', 500);

 select * from tbl_Fees
 insert into tbl_Fees (RollNo,FeeHeader,FeeAmount,PaidAmount) values (555,'Admission',5000,3000);