GRID VIEW HANDLING CONCEPT

Your project or website must be ASP.NET AJAX enabled website. Because we are going to add the GridView in an UpdatePanel. So your GridView control will be look smart without unnecessary postbacks. You need to create a Customer Table with 6 columns for Customer Code[Code], Name[Name], Gender[Gender], City[City], State[State] and Customer Type[Type], with your desired data types. Then create a class file in your App_Code folder and create a Default.aspx along with code-behind file Default.aspx.cs.

Step 1. Create Class File ‘CustomersCls.cs’

We need to create a class file to do database manipulations such as select, insert, delete and update data in the Customer Table. So we add a class file as ‘CustomersCls.cs’ in App_Code section. Let us write five methods in the class file as follows

public void Insert(string CustomerName, string Gender, string City, string State, string CustomerType) {     // Write your own Insert statement blocks } public DataTable Fetch() {   // Write your own Fetch statement blocks, this method should return a DataTable } public DataTable FetchCustomerType() {   // Write your own Fetch statement blocks to fetch Customer Type from its master table and this method should return a DataTable } public void Update(int CustomerCode, string CustomerName, string Gender, string City,  string CustomerType) {   // Write your own Update statement blocks. } public void Delete(int CustomerCode) {   // Write your own Delete statement blocks. }

Step 2: Make Design File ‘Default.aspx’

In the Default.aspx page, add an UpdatePanel control. Inside the UpdatePanel, add a GridView, set AutoGenerateColumns as False. Change the ShowFooter Flag to True and set the DataKeyNames your column name for Customer Code and Customer Type, in our case it is Code and Type. Then click on the Smart Navigation Tag of the GridView control, choose Add New Column and add 5 BoundField columns with DataField values as Name, Gender, City, State and Type, plus 2 CommandField columns with one for Edit/Update and another for Delete functions. Now your GridView control is ready. But as first step, we need to add some new records into the database. For that we need to place the controls in the Footer row. So we have to convert all these BoundField columns as TemplateField columns. To do this again, click on the Smart Navigation Tag on the GridView choose Edit Columns, the Field’s property window will open. Select column by column from Name to Customer Type, include also Edit column, and select ‘Convert this field into a TemplateField’. Now all the BoundField columns will be converted to TemplateField columns except the Delete column.

Column[0] – Name Right click on the GridView control, select Edit Template, choose column[0] – Name, you can view a label placed in the ItemTemplate section and a TextBox placed in the EditItemTemplate section. Add another Texbox in the FooterTemplate section and name it as txtNewName. Column[1] - Gender Now again select Edit Template, choose column[1] - Gender, replace the TextBox with a DropDownList, name it as cmbGender, add Male and Female as their ListItem values. On the Edit DataBindings of the cmbGender, add Eval("Gender") to its selectedvalue. Add another DropDownList in the FooterTemplate section and name it as cmbNewGender. Column[2] –City & Column[3] - State Add Texboxes in both column’s FooterTemplate section and name it as txtNewCity and txtNewState respectively.

Column[4] - Type

In this column’s EditItemTemplate section, replace the TextBox with a DropDownList, name it as cmbType. Also add another DropDownList in the FooterTemplate section and name it as cmbNewType. Both these DropDownList’s we are going to fill with dynamic data from database. So specify both DropDownList’s DataTextField and DataValueField as Type.

Column[5] - Edit

Just add a link button into the FooterTemplate section, specify its CommandName property as ‘AddNew’.

For your persual, we have provided the complete source code of the GridView control below. The State column in our sample is read-only. So you cannot find TextBox for that column in the EditItemTemplate section.

Click here to view Source Code of the GridView Control [Show full code..]

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataKeyNames="Code, Type" OnRowCancelingEdit="GridView1_RowCancelingEdit" OnRowDataBound="GridView1_RowDataBound" OnRowEditing="GridView1_RowEditing" OnRowUpdating="GridView1_RowUpdating" OnRowCommand="GridView1_RowCommand" ShowFooter="True" OnRowDeleting="GridView1_RowDeleting"> <Columns> <asp:TemplateField HeaderText="Name" SortExpression="Name"> <EditItemTemplate>   <asp:TextBox ID="txtName" runat="server" Text='<%# Eval("Name") %>'></asp:TextBox> </EditItemTemplate> <FooterTemplate>   <asp:TextBox ID="txtNewName" runat="server"></asp:TextBox> </FooterTemplate> <ItemTemplate>   <asp:Label ID="Label2" runat="server" Text='<%# Bind("Name") %>'></asp:Label> </ItemTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="Gender"> <EditItemTemplate>   <asp:DropDownList ID="cmbGender" runat="server" SelectedValue='<%# Eval("Gender") %>'>     <asp:ListItem Value="Male" Text="Male"></asp:ListItem>     <asp:ListItem Value="Female" Text="Female"></asp:ListItem>   </asp:DropDownList> </EditItemTemplate> <ItemTemplate>   <asp:Label ID="Label2" runat="server" Text='<%# Eval("Gender") %>'></asp:Label> </ItemTemplate> <FooterTemplate>   <asp:DropDownList ID="cmbNewGender" runat="server" >     <asp:ListItem Selected="True" Text="Male" Value="Male"></asp:ListItem>     <asp:ListItem Text="Female" Value="Female"></asp:ListItem> </asp:DropDownList> </FooterTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="City"> <EditItemTemplate>   <asp:TextBox ID="txtCity" runat="server" Text='<%# Bind("City") %>'></asp:TextBox> </EditItemTemplate> <FooterTemplate>   <asp:TextBox ID="txtNewCity" runat="server" ></asp:TextBox> </FooterTemplate> <ItemTemplate>   <asp:Label ID="Label3" runat="server" Text='<%# Bind("City") %>'></asp:Label> </ItemTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="State" SortExpression="State"> <EditItemTemplate>   <asp:Label ID="Label1" runat="server" Text='<%# Eval("State") %>'></asp:Label> </EditItemTemplate> <FooterTemplate>   <asp:TextBox ID="txtNewState" runat="server" ></asp:TextBox> </FooterTemplate> <ItemTemplate>   <asp:Label ID="Label4" runat="server" Text='<%# Bind("State") %>'></asp:Label> </ItemTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="Type"> <EditItemTemplate>   <asp:DropDownList ID="cmbType" runat="server" DataTextField="Type" DataValueField="Type"> </asp:DropDownList> </EditItemTemplate> <ItemTemplate>   <asp:Label ID="Label5" runat="server" Text='<%# Eval("Type") %>'></asp:Label> </ItemTemplate> <FooterTemplate>   <asp:DropDownList ID="cmbNewType" runat="server" DataTextField="Type" DataValueField="Type"> </asp:DropDownList> </FooterTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="Edit" ShowHeader="False"> <EditItemTemplate>   <asp:LinkButton ID="LinkButton1" runat="server" CausesValidation="True" CommandName="Update" Text="Update"></asp:LinkButton>   <asp:LinkButton ID="LinkButton2" runat="server" CausesValidation="False" CommandName="Cancel" Text="Cancel"></asp:LinkButton> </EditItemTemplate> <FooterTemplate>   <asp:LinkButton ID="LinkButton2" runat="server" CausesValidation="False" CommandName="AddNew" Text="Add New"></asp:LinkButton> </FooterTemplate> <ItemTemplate>   <asp:LinkButton ID="LinkButton1" runat="server" CausesValidation="False" CommandName="Edit" Text="Edit"></asp:LinkButton> </ItemTemplate> </asp:TemplateField> <asp:CommandField HeaderText="Delete" ShowDeleteButton="True" ShowHeader="True" /> </Columns> </asp:GridView>

Step 3: Make Code-behind File ‘Default.aspx.cs’

Now we are going to do the code-behind part of this page. Les us explain you event by event coding on each methods. In the code-behind page, create an instance for the Customer class as follows

CustomersCls customer=new CustomersCls();

Then create a private method 'FillCustomerInGrid' to retrieve the existing customer list from the database and bind it to the GridView. The CustomersCls class’s Fetch() method is used and it returns the data to a DataTable. On first stage it will return empty rows. So you cannot see any header, data or even footer rows of the GridView control. You can only see an empty space or you see only the EmptyDataText. So you cannot add any new data from the footer row.

private void FillCustomerInGrid() {    DataTable dtCustomer= customer.Fetch();  if (dtCustomer.Rows.Count>0)  {     GridView1.DataSource = dtCustomer;     GridView1.DataBind();  }  else  {       dtCustomer.Rows.Add(dtCustomer.NewRow());       GridView1.DataSource = dtCustomer;       GridView1.DataBind();       int TotalColumns = GridView1.Rows[0].Cells.Count;       GridView1.Rows[0].Cells.Clear();       GridView1.Rows[0].Cells.Add(new TableCell());       GridView1.Rows[0].Cells[0].ColumnSpan = TotalColumns;       GridView1.Rows[0].Cells[0].Text = "No Record Found";   } }

In this article, we have provided a workaround to fix this problem. Closely look at the method FillCustomerInGrid, there is a conditional statement to check the rows exists in DataTable or not. Now go to the else part of the if statement, see the block of code we provided there. Simply we have added an empty row to the DataTable. Then bind it to the GridView control. To give a professional look to the GridView control, we do little bit more by providing ColumnSpan and set a Text as "No Record Found", this text will be displayed if the GridView is empty without any rows and you can see both the Header and Footer of the GridView control.

Initialize GridView control

In the page load event, we have to call this FillCustomerInGrid method as follows,

protected void Page_Load(object sender, EventArgs e) {   If (!IsPostBack)   {      FillCustomerInGrid();    } }

Fill DropDownList in GridView with dynamic values

In column[4] - Type, there are two DropDownList controls, one in the EditItemTemplate section (cmbType) and another in FooterTemplate (cmbNewType). We have to fill both these DropDownList controls with some dynamic data. If you look at our CustomersCls class, we have a separate method called FetchCustomerType. In the RowDataBound event of the GridView control insert the following code.

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e) {   if (e.Row.RowType == DataControlRowType.DataRow)   {    DropDownList cmbType = (DropDownList)e.Row.FindControl("cmbType");   if (cmbType != null)   {     cmbType.DataSource = customer.FetchCustomerType();     cmbType.DataBind();     cmbType.SelectedValue = GridView1.DataKeys[e.Row.RowIndex].Values[1].ToString();    }  } if (e.Row.RowType == DataControlRowType.Footer) {     DropDownList cmbNewType = (DropDownList)e.Row.FindControl("cmbNewType");     cmbNewType.DataSource = customer.FetchCustomerType();     cmbNewType.DataBind();  } }

Previously in this article, we have set the DataKeyNames values as Code, Type. If you see in the above code, we use one of the DataKeyNames value as the SelectedValue for the cmbType control, this is to retain the value of the cmbType in EditMode. The index value of Code is 0 and Type is 1. So we use as follows

cmbType.SelectedValue = GridView1.DataKeys[e.Row.RowIndex].Values[1].ToString();

So far we have initialized the GridView control with the datatable and also make some values to be filled in the Footer DropDownList cmbNewType. Run the application, you can see the GridView only with the Footer row and data in the cmbNewType control. Let us start to code for adding new records into the database when we click ‘Add New’ linkbutton.

Add New Records from GridView control

Create an event for the GridView’s RowCommand and add the following code in it.

protected void GridView1_RowCommand(object sender, GridViewCommandEventArgs e) {   if (e.CommandName.Equals("AddNew"))   {    TextBox txtNewName=(TextBox)GridView1.FooterRow.FindControl("txtNewName");    DropDownList cmbNewGender = (DropDownList)GridView1.FooterRow.FindControl("cmbNewGender");    TextBox txtNewCity = (TextBox)GridView1.FooterRow.FindControl("txtNewCity");    TextBox txtNewState = (TextBox)GridView1.FooterRow.FindControl("txtNewState");    DropDownList cmbNewType = (DropDownList)GridView1.FooterRow.FindControl("cmbNewType");    customer.Insert(txtNewName.Text, cmbNewGender.SelectedValue, txtNewCity.Text, txtNewState.Text, cmbNewType.SelectedValue) ;       FillCustomerInGrid();   } }

In the above code, we are declaring and finding the controls in the GridView’s footer section and use the CustomersCls class insert method to add the new data into the database. Then we are calling the FillCustomerInGrid method to fill the GridView control with the newly inserted values. Now save everything and run your application. Put some test data in the Textboxes and select some values in the DropDownLists and click on the Add New linkbutton. You can see data inserted into the database and listed in the GridView control.

Edit and Update in GridView In the RowEditing event of the GridView, add the following lines of code. This will switch a specific row of the GridView to Edit Mode.
protected void GridView1_RowEditing(object sender, GridViewEditEventArgs e) {   GridView1.EditIndex = e.NewEditIndex;   FillCustomerInGrid(); }
After the GridView swithes to Edit Mode, you can view the TextBoxes and DropDownlList controls along with Update and Cancel linkbuttons in the Edit mode. To cancel this action, add the following two lines of code in the GridView’s RowCancelingEdit event.
protected void GridView1_RowCancelingEdit(object sender, GridViewCancelEditEventArgs e) {   GridView1.EditIndex = -1;    FillCustomerInGrid(); }

You can update the data to the customer table, by adding the following lines of code in the GridView’s RowUpdating event.

protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e) {   TextBox txtName = (TextBox)GridView1.Rows[e.RowIndex].FindControl("txtName");   DropDownList cmbGender = (DropDownList)GridView1.Rows[e.RowIndex].FindControl("cmbGender");   TextBox txtCity = (TextBox)GridView1.Rows[e.RowIndex].FindControl("txtCity");   DropDownList cmbType = (DropDownList)GridView1.Rows[e.RowIndex].FindControl("cmbType");  customer.Update(GridView1.DataKeys[e.RowIndex].Values[0].ToString(),txtName.Text, cmbGender.SelectedValue,txtCity.Text, cmbType.SelectedValue);   GridView1.EditIndex = -1;   FillCustomerInGrid(); }