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Posts Tagged ‘Datagrid’

custom paging of the datagrid or gridview

Posted by Viral Sarvaiya on August 20, 2009


hear i demonstrate the custom paging of the datagrid or gridview.

in the client side take the datagrid or grid view

here i take the datagrid,


<table>

<tr>
<td>

<asp:datagrid id="dgMake" runat="server" AutoGenerateColumns="False" Width="100%"
CellPadding="5" GridLines="None" AllowPaging="true">

<Columns>
<asp:TemplateColumn>
<HeaderStyle HorizontalAlign="Left" Width="100"></HeaderStyle>
<HeaderTemplate>Part</HeaderTemplate>
<ItemStyle HorizontalAlign="Left" Width="100"></ItemStyle>
<ItemTemplate><%#Container.DataItem("part")%></ItemTemplate>
</asp:TemplateColumn>

<asp:TemplateColumn>
<HeaderStyle HorizontalAlign="Left"></HeaderStyle>
<HeaderTemplate>Description</HeaderTemplate>
<ItemStyle HorizontalAlign="Left"></ItemStyle>
<ItemTemplate><%#Container.DataItem("description")%></ItemTemplate>
</asp:TemplateColumn>

</Columns>
<PagerStyle Visible="False"></PagerStyle>
</asp:datagrid>

</td>
</tr>

in the second raw, i add the link buttons as below,


<tr>
<td valign="top" align="right" bgcolor="#e1e4e6" style="padding:10px 10px 10px 60px;text-align:right;">
<asp:linkbutton id="FirstButton" onclick="PagerButtonClick" runat="server" CssClass="contant" CommandArgument="0"> First Page</asp:linkbutton><asp:label id="lblFirstLine" runat="server">&nbsp;|&nbsp;</asp:label>
<asp:linkbutton id="PrevButton" onclick="PagerButtonClick" runat="server" CssClass="contant" CommandArgument="prev">Prev</asp:linkbutton><asp:label id="lblLine" runat="server">&nbsp;|&nbsp;</asp:label>
<asp:linkbutton id="NextButton" onclick="PagerButtonClick" runat="server" CssClass="contant" CommandArgument="next">Next</asp:linkbutton><asp:label id="lblLastLine" runat="server">&nbsp;|&nbsp;</asp:label>
<asp:linkbutton id="LastButton" onclick="PagerButtonClick" runat="server" CssClass="contant" CommandArgument="last"> Last Page</asp:linkbutton>
</td>
</tr>

in the code-behind file, bind the datagrid as below,

define the page size of the datagrid in the page load


dgMake.PageSize = 50

then call this function in the postback false part of the page load.


sub bind_datagrid()

Dim ds As New DataSet

ds = classobject.fiunctionname()

If ds.Tables(0).Rows.Count > 0 Then

dgMake.DataSource = ds

dgMake.DataBind()

firstprev()

Else

dgMake.DataSource = ds
dgMake.DataBind()

FirstButton.Visible = False
PrevButton.Visible = False
NextButton.Visible = False
LastButton.Visible = False
lblFirstLine.Visible = False
lblLastLine.Visible = False
lblLine.Visible = False

End If
End Sub

Public Sub firstprev()
If dgMake.CurrentPageIndex <> 0 Then
Call Prev_Buttons()
FirstButton.Visible = True
PrevButton.Visible = True
lblFirstLine.Visible = True
Else
FirstButton.Visible = False
PrevButton.Visible = False
lblFirstLine.Visible = False
End If

'To Display Next/Last Page buttons

If dgMake.CurrentPageIndex <> (dgMake.PageCount - 1) Then
Call Next_Buttons()
NextButton.Visible = True
LastButton.Visible = True
lblLastLine.Visible = True
Else
NextButton.Visible = False
LastButton.Visible = False
lblLastLine.Visible = False
End If

If dgMake.CurrentPageIndex > 0 And dgMake.CurrentPageIndex < dgMake.PageCount - 1 Then
lblLine.Visible = True
Else
lblLine.Visible = False
End If

End Sub

Sub Prev_Buttons()
Dim PrevSet As String
If dgMake.CurrentPageIndex + 1 <> 1 Then
PrevSet = dgMake.PageSize
PrevButton.Text = ("Prev")
End If
End Sub

Sub Next_Buttons()
Dim NextSet As String
If dgMake.CurrentPageIndex + 1 < dgMake.PageCount Then
NextSet = dgMake.PageSize
NextButton.Text = ("Next")
End If
End Sub

Sub PagerButtonClick(ByVal sender As Object, ByVal e As EventArgs)
Dim arg As String = sender.CommandArgument
Select Case arg
Case "next"
'The next Button was Clicked
If (dgMake.CurrentPageIndex < (dgMake.PageCount - 1)) Then
dgMake.CurrentPageIndex += 1
End If

Case "prev"
'The prev button was clicked
If (dgMake.CurrentPageIndex > 0) Then
dgMake.CurrentPageIndex -= 1
End If

Case "last"
'The Last Page button was clicked
dgMake.CurrentPageIndex = (dgMake.PageCount - 1)

Case Else
'The First Page button was clicked
dgMake.CurrentPageIndex = Convert.ToInt32(arg)
End Select
'selpagecombo()
'Now, bind the data!
bind_datagrid()
End Sub

so the page will be bind to 50 records.

enjoy coding…..

Posted in ASP.NET | Tagged: , , | Leave a Comment »

Gridview – insert, update, delete

Posted by Viral Sarvaiya on July 27, 2009


Pre-requisites

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 State,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.

Source Code of the GridView Control

<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();</span>

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,CustomerType.SelectedValue);
GridView1.EditIndex = -1;
FillCustomerInGrid();
}

The above block of codes in RowUpdating event, finds the control in the GridView, takes those values in pass it to the CustomersCls class Update method.

The first parameter GridView1.DataKeys[e.RowIndex].Values[0].ToString() will return the Code of the Customer. That is the unique code for each customer to perform update function.

Delete in GridView

To delete a row from the customer table, add the following lines of code in the GridView’s RowDeleting event. Here you have to pass the unique Code of customer which is in GridView1.DataKeys[e.RowIndex].Values[0].ToString() to the Delete method of the CustomersCls class.

protected void GridView1_RowDeleting(object sender, GridViewDeleteEventArgs e)
{
customer.Delete(GridView1.DataKeys[e.RowIndex].Values[0].ToString());
FillCustomerInGrid();
}

Posted in ASP.NET | Tagged: , , , , , | 2 Comments »

Differences between Datagrid, Datalist and Repeater?

Posted by Viral Sarvaiya on July 13, 2009


1. Datagrid has paging while Datalist doesnt.
2. Datalist has a property called repeat. Direction = vertical/horizontal. (This is of great help in designing layouts). This is not there in Datagrid.
3. A repeater is used when more intimate control over html generation is required.
4. When only checkboxes/radiobuttons are repeatedly served then a checkboxlist or radiobuttonlist are used as they involve fewer overheads than a Datagrid.
The Repeater repeats a chunk of HTML you write, it has the least functionality of the three. DataList is the next step up from a Repeater; accept you have very little control over the HTML that the control renders. DataList is the first of the three controls that allow you Repeat-Columns horizontally or vertically. Finally, the DataGrid is the motherload. However, instead of working on a row-by-row basis, you’re working on a column-by-column basis. DataGrid caters to sorting and has basic paging for your disposal. Again you have little contro, over the HTML. NOTE: DataList and DataGrid both render as HTML tables by default.
Out of the 3 controls, I use the Repeater the most due to its flexibility w/ HTML. Creating a Pagination scheme isn’t that hard, so I rarely if ever use a DataGrid. Occasionally I like using a DataList because it allows me to easily list out my records in rows of three for instance.

Datagrid is most restrictive as regards to customization followed by DataList and finally Repeater is the most customizable.

Datagrid has built in paging sorting and editing capabilities which are not there with the other two controls. So if you want users to sort / page / edit data datagrid is the natural choice.

DataList and repeater have better performance than datagrid. So if performance is a major concern for example a site with large number of concurrent visitors then you could think of datalist or repeater.

Repeater is the most customizable. It allows you to create structures like nested lists for example.

A datagrid row displays one record from the data source while a datalist row can display more than one records (set by RepeatColumns property)

Datagrid and Datalist are derived from WebControl while Repeater is not and so does not have the stylistic properties of web controls.

All are similar in that they have a datasource property and ItemCreated ItemDataBound and ItemCommand events.

Posted in ASP.NET | Tagged: , , | Leave a Comment »

 
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