In this article I will explain with an example, how to use string.Format function with Eval (DataBinder.Eval) function in ASP.Net with C# and VB.Net.
Eval (DataBinder.Eval) function is used to bind data in controls inside GridView, DataList, Repeater, DetailsView, etc. and using string.Format multiple values can be set to a single control.
 
 
HTML Markup
The below HTML Markup consists of an ASP.Net GridView with 4 columns. The first and fourth column have HyperLinks inside the ItemTemplate of TemplateField.
<asp:GridView ID="GridView1" HeaderStyle-BackColor="#3AC0F2" HeaderStyle-ForeColor="White"
    RowStyle-BackColor="#A1DCF2" AlternatingRowStyle-BackColor="White" AlternatingRowStyle-ForeColor="#000"
    runat="server" AutoGenerateColumns="false">
    <Columns>
        <asp:TemplateField HeaderText = "Id" ItemStyle-Width="30">
            <ItemTemplate>
                <asp:HyperLink runat="server" NavigateUrl='<%# Eval("Id", "~/Details.aspx?Id={0}") %>'
                    Text='<%# Eval("Id") %>' />
            </ItemTemplate>
        </asp:TemplateField>
        <asp:BoundField DataField="Name" HeaderText="Name" ItemStyle-Width="150" />
        <asp:BoundField DataField="Country" HeaderText="Country" ItemStyle-Width="150" />
        <asp:TemplateField>
            <ItemTemplate>
                <asp:HyperLink runat="server" NavigateUrl='<%# string.Format("~/Details.aspx?Id={0}&Name={1}&Country={2}",
                    HttpUtility.UrlEncode(Eval("Id").ToString()), HttpUtility.UrlEncode(Eval("Name").ToString()), HttpUtility.UrlEncode(Eval("Country").ToString())) %>'
                    Text="View Details" />
            </ItemTemplate>
        </asp:TemplateField>
    </Columns>
</asp:GridView>
 
NavigateUrl with Single QueryString Parameter
NavigateUrl='<%# Eval("Id", "~/Details.aspx?Id={0}") %>'
 
The first column HyperLink passes only one QueryString Parameter and hence the same has been set using the Eval function.
 
NavigateUrl with Multiple QueryString Parameters
NavigateUrl='<%# string.Format("~/Details.aspx?Id={0}&Name={1}&Country={2}",
HttpUtility.UrlEncode(Eval("Id").ToString()), HttpUtility.UrlEncode(Eval("Name").ToString()), HttpUtility.UrlEncode(Eval("Country").ToString())) %>'
 
Here we need to pass three QueryString parameters, thus we need to concatenate the Eval functions of the three fields using String Format function.
 
 
Namespaces
You will need to import the following namespace.
C#
using System.Data;
 
VB.Net
Imports System.Data
 
 
Binding the GridView
I have made use of DataTable with some dummy values for this article.
C#
protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        DataTable dt = new DataTable();
        dt.Columns.AddRange(new DataColumn[3] { new DataColumn("Id"), new DataColumn("Name"), new DataColumn("Country") });
        dt.Rows.Add(1, "John Hammond", "United States");
        dt.Rows.Add(2, "Mudassar Khan", "India");
        dt.Rows.Add(3, "Suzanne Mathews", "France");
        dt.Rows.Add(4, "Robert Schidner", "Russia");
        GridView1.DataSource = dt;
        GridView1.DataBind();
    }
}
 
VB.Net
Protected Sub Page_Load(sender As Object, e As EventArgs) Handles Me.Load
    If Not Me.IsPostBack Then
        Dim dt As New DataTable()
        dt.Columns.AddRange(New DataColumn(2) {New DataColumn("Id"), New DataColumn("Name"), New DataColumn("Country")})
        dt.Rows.Add(1, "John Hammond", "United States")
        dt.Rows.Add(2, "Mudassar Khan", "India")
        dt.Rows.Add(3, "Suzanne Mathews", "France")
        dt.Rows.Add(4, "Robert Schidner", "Russia")
        GridView1.DataSource = dt
        GridView1.DataBind()
    End If
End Sub
 
Using string.Format with Eval (DataBinder.Eval) function in ASP.Net with C# and VB.Net
 
 
Accessing and displaying the QueryString Values on destination page
On the destination page I am extracting the QueryString values from the URL and displaying them on page.
HTML Markup
<table>
    <tr>
        <td>
            <b>Id</b>
        </td>
        <td>
            <asp:Label ID="lblId" runat="server"></asp:Label>
        </td>
    </tr>
    <tr>
        <td>
            <b>Name</b>
        </td>
        <td>
            <asp:Label ID="lblName" runat="server"></asp:Label>
        </td>
    </tr>
        <tr>
        <td>
            <b>Country</b>
        </td>
        <td>
            <asp:Label ID="lblCountry" runat="server"></asp:Label>
        </td>
    </tr>
</table>
 
C#
protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        lblId.Text = HttpUtility.UrlDecode(Request.QueryString["Id"]);
        lblName.Text = HttpUtility.UrlDecode(Request.QueryString["Name"]);
        lblCountry.Text = HttpUtility.UrlDecode(Request.QueryString["Country"]);
    }
}
 
VB.Net
Protected Sub Page_Load(sender As Object, e As EventArgs) Handles Me.Load
    If Not Me.IsPostBack Then
        lblId.Text = HttpUtility.UrlDecode(Request.QueryString("Id"))
        lblName.Text = HttpUtility.UrlDecode(Request.QueryString("Name"))
        lblCountry.Text = HttpUtility.UrlDecode(Request.QueryString("Country"))
    End If
End Sub
 
Using string.Format with Eval (DataBinder.Eval) function in ASP.Net with C# and VB.Net
 
 
Demo
View Demo
 
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