This is the second installment of the article DropDownList Inside the GridView. In the previous article DropDownList Inside the GridView I talked about how you can populate the DropDownList inside the GridView with different data depending on the row of the article using a DataSet. In this article I will show demonstrate that how you can achieve the same behavior using Entity Classes.

Introduction:

This is the second installment of the article, DropDownList Inside the GridView. In the previous article DropDownList Inside the GridView I talked about how you can populate the DropDownList inside the GridView with different data using a DataSet. In this article I will demonstrate that how you can achieve the same behavior using Entity Classes.

Analysis:

The first thing that you need to do is to create the Category and Product classes. Take a look at both classes below:

public class Product { private int _productID; private string _productName; public int ProductID { get { return _productID; } set { _productID = value; } } public string ProductName { get { return _productName; } set { _productName = value; } } public Product(int productID, string productName) { _productID = productID; _productName = productName; } public Product() { }

Since, a single category can have multiple products that is why I am going to declare a list of Product inside the Category class. Take a look at the Category class to have better idea.

public class Category { private int _categoryID; private string _categoryName; private List<Product> _productList = new List<Product>(); public int CategoryID { get { return _categoryID; } set { _categoryID = value; } } public string CategoryName { get { return _categoryName; } set { _categoryName = value; } } public List<Product> ProductList { get { return _productList; } set { _productList = value; } } public Category(int categoryID, string categoryName) { _categoryID = categoryID; _categoryName = categoryName; } public Category() { } }

After creating the required classes we need to create some dummy data which will be used to populate the DropDownLists. In the code below I demonstrated that how you can create dummy categories and populate dummy products for the particular category. 

private List<Category> categoryList = new List<Category>(); private void FillList() { for (int j = 1; j <= 10; j++) { Category category = new Category(j,"Category"+j); for (int i = 1; i <= 10; i++) { category.ProductList.Add(new Product(i, "ProductA" + j + i)); } categoryList.Add(category); }   // Bind the list to the GridView GridView1.DataSource = categoryList; GridView1.DataBind(); }

The FillList() method above populates the Category class with dummy categories and products. Now, the only thing left to do is to fill the dummy data into the DropDownList. Take a look at the code below:

private int _counter = 0; protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e) { if (e.Row.RowType == DataControlRowType.DataRow) { DropDownList ddl = (DropDownList)e.Row.FindControl("DropDownList1"); ddl.DataSource = categoryList[_counter].ProductList; ddl.DataTextField = "ProductName"; ddl.DataBind(); // increment the counter _counter++; } }

The code above is implemented in the GridView_RowDataBound event, which is fired every time a row is bound on the GridView. The heart of this application is the line ddl.DataSource = categoryList[_counter].ProductList; which retrieves the product list of a particular category and assign it to the DataSource property of the DropDownList control. After the product list is assigned to the data source I simply assign the ProductName property to the DataTextField property of the DropDownList.

Take a look at the image below to have a clear idea what the GridView looks like at runtime.

I hope you like article, happy coding!