Storing DataTable in ViewState in Asp.net Example using C#.Net

How to store datatable in viewstate:

Introduction:

In my previous article i explained what is viewstate in asp.net, viewstate postback count example in asp.net,WPF Architecture,Asp.Net Validation Controls Tutorial,Asp.Net Ajax Tutorial and various articles on WPF and Asp.Net. Now i will explain how to store datatable in viewstate and retrieve it back.

Description:

In this example i will get data table from database and store it in viewstate in page load event and then in button click event i will get data table from viewstate and populates it in gridview. This is the example how to store large volumes of data in viewstate.

     Take form which contains a label,a button and gridview like below

<form id="form1" runat="server"> <div> <asp:GridView ID="GridView1" runat="server" CellPadding="4" ForeColor="#333333" GridLines="None" style="z-index: 1; left: 279px; top: 121px; position: absolute; height: 133px; width: 187px"> <alternatingrowstyle BackColor="White" /> <editrowstyle BackColor="#7C6F57" /> <footerstyle BackColor="#1C5E55" Font-Bold="True" ForeColor="White" /> <headerstyle BackColor="#1C5E55" Font-Bold="True" ForeColor="White" /> <pagerstyle BackColor="#666666" ForeColor="White" HorizontalAlign="Center" /> <rowstyle BackColor="#E3EAEB" /> <selectedrowstyle BackColor="#C5BBAF" Font-Bold="True" ForeColor="#333333" /> <sortedascendingcellstyle BackColor="#F8FAFA" /> <sortedascendingheaderstyle BackColor="#246B61" /> <sorteddescendingcellstyle BackColor="#D4DFE1" /> <sorteddescendingheaderstyle BackColor="#15524A" /> </asp:GridView> <asp:Button ID="Button1" runat="server" onclick="Button1_Click" style="z-index: 1; left: 284px; top: 80px; position: absolute" Text="LoadData" /> <asp:Label ID="Label1" runat="server" BackColor="#CCCCCC" ForeColor="#FF0066" style="z-index: 1; left: 325px; top: 54px; position: absolute; width: 354px"></asp:Label> </div> </form>
In the page load event and button click event write below code
protected void Page_Load(object sender, EventArgs e) { SqlConnection con = new SqlConnection("database=cs9db;user id=sa;password=9290812112;data source=(local);"); SqlDataAdapter da = new SqlDataAdapter("Select * from emp where deptno="+30, con); DataTable dt = new DataTable(); da.Fill(dt); ViewState["EmpTable"] = dt;// storing datatable in viewstate Label1.Text = "Data Table stored in viewstate"; } protected void Button1_Click(object sender, EventArgs e) { GridView1.DataSource = (DataTable)ViewState["EmpTable"];// retrieving datatable from viewstate GridView1.DataBind(); Label1.Text = "View state datatable is displayed in gridview"; }

In the page load event i am getting datatable from emp table and storing it in viewstate. in button click event i am getting viewstate emptable and binding that table to gridview. In this way you can store large amount of data in viewstate but it will increase the page size.

 

Conclusion:

I hope you got an idea how to store large data like datatables in viewstate.

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