Displaying different pictures in GridView depending on the data? - asp.net

Question

I am creating a WEB report in Visual Studio 2010 in VB.net. The report needs to display a table (please see the attached image). I am thinking to use the GridView component which i think it's the most appropriate one to choose. In the database there are students' data and marks. I can't alter the database in any way and i have to use Visual Studio 2010 with VB.
What i need to do is to show 3 different pictures(for example) depend on the student's marks. I got the pictures file in PNGs but this can be flexible.For example, over 70 will be a Smile picture. over 60 will be the Normal face. and over 40 will be the picture with no smile. I bit difficult for me to explain but i hope u get my point.
So pls advice me how can i achieve this. I am quite a newbie to this pls put as detail as you can. if there is a choice between client and server side script, i prefer server side script. Data source can be flexible (sql, or linq or anything).

Answer 1

You should use RowDataBound to bind data to controls in your GridView.
Following is a complete sample with aspx and codebehind(says more than thousand words):
<style type="text/css">
.GridViewRowStyle
{
background-color: #A0CFEC;
color:Blue;
}
.GridViewAlternatingRowStyle
{
background-color:White;
color:#15317E;
}
.GridViewHeaderStyle
{
background-color:White;
color:#15317E;
}
</style>
<asp:GridView ID="GridStudents" AutoGenerateColumns="false" GridLines="None" runat="server">
<RowStyle CssClass="GridViewRowStyle" />
<AlternatingRowStyle CssClass="GridViewAlternatingRowStyle" />
<HeaderStyle CssClass="GridViewHeaderStyle" />
<Columns>
<asp:TemplateField HeaderText="Student">
<ItemTemplate>
<asp:label runat="server" ID="LblStudent" Text='<%# Bind("Student") %>'></asp:label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Mark">
<ItemTemplate>
<asp:label runat="server" ID="LblMark" Text='<%# Bind("Mark") %>'></asp:label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="">
<ItemTemplate>
<asp:Image runat="server" ID="ImgSmiley" />
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
Codebehind(with sample-data):
Private Sub GridStudents_RowDataBound(sender As Object, e As System.Web.UI.WebControls.GridViewRowEventArgs) Handles GridStudents.RowDataBound
Select Case e.Row.RowType
Case DataControlRowType.DataRow
Dim row = DirectCast(e.Row.DataItem, DataRowView)
Dim ImgSmiley = DirectCast(e.Row.FindControl("ImgSmiley"), Image)
Select Case DirectCast(row("Mark"), Int32)
Case Is < 50
ImgSmiley.ImageUrl = "~/Images/Smiley_Grim.png"
ImgSmiley.ToolTip = "bad"
Case Is < 70
ImgSmiley.ImageUrl = "~/Images/Smiley_Def.png"
ImgSmiley.ToolTip = "ok"
Case Else
ImgSmiley.ImageUrl = "~/Images/Smiley_Laugh.png"
ImgSmiley.ToolTip = "fine"
End Select
End Select
End Sub
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If Not IsPostBack Then
BindData()
End If
End Sub
Private Sub BindData()
Dim tblStudent As New DataTable("Students")
Dim colStudent = New DataColumn("Student", GetType(String))
Dim colMark As New DataColumn("Mark", GetType(Int32))
tblStudent.Columns.Add(colStudent)
tblStudent.Columns.Add(colMark)
Dim newRow = tblStudent.NewRow
newRow("Student") = "Tom"
newRow("Mark") = 70
tblStudent.Rows.Add(newRow)
newRow = tblStudent.NewRow
newRow("Student") = "Bob"
newRow("Mark") = 40
tblStudent.Rows.Add(newRow)
newRow = tblStudent.NewRow
newRow("Student") = "Danny"
newRow("Mark") = 60
tblStudent.Rows.Add(newRow)
newRow = tblStudent.NewRow
newRow("Student") = "Sussie"
newRow("Mark") = 40
tblStudent.Rows.Add(newRow)
GridStudents.DataSource = tblStudent
GridStudents.DataBind()
End Sub