21. Adding Insert, Update and Delete Functionality on Product Module

In the previous episode, we have successfully created methods to INSET, UPDATE and DELETE in Data Access Layer (DAL) for our Product Module in BILLING AND INVENTORY MANAGEMENT SYSTEM IN C#.
In this episode, we will use these methods to add actual functionality to Add New Product, Update & Delete Existing Products.
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Some to the events and codes to Add these features are as follows:

1. Add Button Click Event to Insert New Product

Here, we will double click on Add Button to create the button click event, and the code inside the Add Button Click Event is as follows

        private void btnAdd_Click(object sender, EventArgs e)
        {
            //Get All the Values from Product Form
            p.name = txtName.Text;
            p.category = cmbCategory.Text;
            p.description = txtDescription.Text;
            p.rate = decimal.Parse(txtRate.Text);
            p.qty = 0;
            p.added_date = DateTime.Now;
            //Getting username of logged in user
            String loggedUsr = frmLogin.loggedIn;
            userBLL usr = udal.GetIDFromUsername(loggedUsr);

            p.added_by = usr.id;

            //Create Boolean variable to check if the product is added successfully or not
            bool success = pdal.Insert(p);
            //if the product is added successfully then the value of success will be true else it will be false
            if(success==true)
            {
                //Product Inserted Successfully
                MessageBox.Show("Product Added Successfully");
                //Calling the Clear Method
                Clear();
                //Refreshing DAta Grid View
                DataTable dt = pdal.Select();
                dgvProducts.DataSource = dt;
            }
            else
            {
                //Failed to Add New product
                MessageBox.Show("Failed to Add New Product");
            }
        }


2. Form Load Event to Display all the added Products in Data Grid View

After the Product is added, we should be able to see the products when we open the form as well as after the product is added, updated and deleted.
So the code to display the products in Data Grid View is as follows

        private void frmProducts_Load(object sender, EventArgs e)
        {
            //Creating DAta Table to hold the categories from Database
            DataTable categoriesDT = cdal.Select();
            //Specify DataSource for Category ComboBox
            cmbCategory.DataSource = categoriesDT;
            //Specify Display Member and Value Member for Combobox
            cmbCategory.DisplayMember = "title";
            cmbCategory.ValueMember = "title";

            //Load all the Products in Data Grid View
            DataTable dt = pdal.Select();
            dgvProducts.DataSource = dt;
        }


3. Clear Method to clear all the text boxes after Product is Inserted, Updated and Deleted

After the Product is Inserted, Updated or Deleted, we need to clear all the text boxes so that we can add other products.
Thus, the code to create this method is as follows

        public void Clear()
        {
            txtID.Text = "";
            txtName.Text = "";
            txtDescription.Text = "";
            txtRate.Text = "";
            txtSearch.Text = "";
        }


4. Row Header Mouse Click Event to Display data in Text boxes

In order to Update or Delete the Products, first we need to select the product from Data Grid View.
So, Row Header Mouse Click Event will help to select the product and display the data in text boxes and the code for this event is as follows

         private void dgvProducts_RowHeaderMouseClick(object sender, DataGridViewCellMouseEventArgs e)
        {
            //Create integer variable to know which product was clicked
            int rowIndex = e.RowIndex;
            //Display the Value on Respective TextBoxes
            txtID.Text = dgvProducts.Rows[rowIndex].Cells[0].Value.ToString();
            txtName.Text = dgvProducts.Rows[rowIndex].Cells[1].Value.ToString();
            cmbCategory.Text = dgvProducts.Rows[rowIndex].Cells[2].Value.ToString();
            txtDescription.Text = dgvProducts.Rows[rowIndex].Cells[3].Value.ToString();
            txtRate.Text = dgvProducts.Rows[rowIndex].Cells[4].Value.ToString();

        }


5. Update Button Click Event To Update the Products

After the product is selected from the Data Grid View, we can modify the values in text boxes and click on Update Button to update the Product.
The code for Update Button Click event is as follows

        private void btnUpdate_Click(object sender, EventArgs e)
        {
            //Get the Values from UI or Product Form
            p.id = int.Parse(txtID.Text);
            p.name = txtName.Text;
            p.category = cmbCategory.Text;
            p.description = txtDescription.Text;
            p.rate = decimal.Parse(txtRate.Text);
            p.added_date = DateTime.Now;
            //Getting Username of logged in user for added by
            String loggedUsr = frmLogin.loggedIn;
            userBLL usr = udal.GetIDFromUsername(loggedUsr);

            p.added_by = usr.id;

            //Create a boolean variable to check if the product is updated or not
            bool success = pdal.Update(p);
            //If the prouct is updated successfully then the value of success will be true else it will be false
            if(success==true)
            {
                //Product updated Successfully
                MessageBox.Show("Product Successfully Updated");
                Clear();
                //REfresh the Data Grid View
                DataTable dt = pdal.Select();
                dgvProducts.DataSource = dt;
            }
            else
            {
                //Failed to Update Product
                MessageBox.Show("Failed to Update Product");
            }
        }


6. Delete Button Click Event To Delete the Selected Product

When the product we want to delete is selected, the product detail will be shown in Textboxes.
Then we can click on Delete Button to Delete the Product. The code for Button Delete Event is as follows

        private void btnDelete_Click(object sender, EventArgs e)
        {
            //GEt the ID of the product to be deleted
            p.id = int.Parse(txtID.Text);

            //Create Bool VAriable to Check if the product is deleted or not
            bool success = pdal.Delete(p);

            //If prouct is deleted successfully then the value of success will true else it will be false
            if(success==true)
            {
                //Product Successfuly Deleted
                MessageBox.Show("Product successfully deleted.");
                Clear();
                //Refresh DAta Grid View
                DataTable dt = pdal.Select();
                dgvProducts.DataSource = dt;
            }
            else
            {
                //Failed to Delete Product
                MessageBox.Show("Failed to Delete Product.");
            }
        }


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BILLING AND INVENTORY MANAGEMENT SYSTEM IN C#