Change ASP.Net DataList Cell Background Color based on condition using C# and VB.Net

Hi akhter,

You need to make use of OnItemDataBound event handler of DataList control.

Inside the OnItemDataBound event handler check the condition and apply BgColor to TableCell.

Refer below sample and modify as per your requirement.

HTML

<asp:DataList ID="dlCustomers" runat="server" RepeatLayout="Table" OnItemDataBound="dlCustomers_OnItemDataBound">
    <HeaderTemplate>
        <table class="table">
            <tr>
                <td>
                    TDID
                </td>
                <td>
                    TDDesc
                </td>
                <td>
                    taskdate
                </td>
                <td>
                    enddate
                </td>
                <td>
                    TDstatus
                </td>
                <td>
                    latedays
                </td>
            </tr>
    </HeaderTemplate>
    <ItemTemplate>
        <tr>
            <td>
                <%# Eval("TDID")%>
            </td>
            <td>
                <%# Eval("TDDesc")%>
            </td>
            <td>
                <%# Eval("taskdate")%>
            </td>
            <td>
                <%# Eval("enddate")%>
            </td>
            <td>
                <%# Eval("TDstatus")%>
            </td>
            <td runat="server" id="tbl">
                <asp:Label ID="lblLateDays" Text='<%# Eval("latedays")%>' runat="server" />
            </td>
        </tr>
    </ItemTemplate>
    <FooterTemplate>
        </table>
    </FooterTemplate>
</asp:DataList>

Namespaces

C#

using System.Data;
using System.Web.UI.HtmlControls;

VB.Net

Imports System.Data

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        DataTable dt = new DataTable();
        dt.Columns.Add("TDID");
        dt.Columns.Add("TDDesc");
        dt.Columns.Add("taskdate");
        dt.Columns.Add("enddate");
        dt.Columns.Add("TDstatus");
        dt.Columns.Add("latedays");
        dt.Rows.Add(1, "hey", "01/02/2019", "04/05/2019", "Pending", "1");
        dt.Rows.Add(2, "Hi", "05/03/2019", "08/06/2019", "USA", "0");
        this.dlCustomers.DataSource = dt;
        this.dlCustomers.DataBind();
    }
}

protected void dlCustomers_OnItemDataBound(object sender, DataListItemEventArgs e)
{
    if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem)
    {
        DataListItem item = e.Item as DataListItem;
        string lateDays = (item.FindControl("lblLateDays") as Label).Text.Trim();
        if (lateDays == "0")
        {
            HtmlTableCell tbl = item.FindControl("tbl") as HtmlTableCell;
            tbl.BgColor = "Red";
        }
    }
}

VB.Net

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Not Me.IsPostBack Then
        Dim dt As DataTable = New DataTable()
        dt.Columns.Add("TDID")
        dt.Columns.Add("TDDesc")
        dt.Columns.Add("taskdate")
        dt.Columns.Add("enddate")
        dt.Columns.Add("TDstatus")
        dt.Columns.Add("latedays")
        dt.Rows.Add(1, "hey", "01/02/2019", "04/05/2019", "Pending", "1")
        dt.Rows.Add(2, "Hi", "05/03/2019", "08/06/2019", "USA", "0")
        Me.dlCustomers.DataSource = dt
        Me.dlCustomers.DataBind()
    End If
End Sub

Protected Sub dlCustomers_OnItemDataBound(ByVal sender As Object, ByVal e As DataListItemEventArgs)
    If e.Item.ItemType = ListItemType.Item OrElse e.Item.ItemType = ListItemType.AlternatingItem Then
        Dim item As DataListItem = TryCast(e.Item, DataListItem)
        Dim lateDays As String = (TryCast(item.FindControl("lblLateDays"), Label)).Text.Trim()

        If lateDays = "0" Then
            Dim tbl As HtmlTableCell = TryCast(item.FindControl("tbl"), HtmlTableCell)
            tbl.BgColor = "Red"
        End If
    End If
End Sub

Screenshot