I have a GridView displaying person records. I want to conditionally show a CommandField or ButtonField based on some property of the underlying record. The idea is to only allow a command to be performed on specific people.
What is the best way to do this? (I'd prefer a declarative solution to a procedural one.)
it could be done when the RowDataBound event fires
protected void GridView_RowDataBound(Object sender, GridViewRowEventArgs e)
{
if(e.Row.RowType == DataControlRowType.DataRow)
{
// Hide the edit button when some condition is true
// for example, the row contains a certain property
if (someCondition)
{
Button btnEdit = (Button)e.Row.FindControl("btnEdit");
btnEdit.Visible = false;
}
}
}
Here's a demo page
markup
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="DropDownDemo._Default" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
<title>GridView OnRowDataBound Example</title>
</head>
<body>
<form id="form1" runat="server">
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false">
<Columns>
<asp:BoundField HeaderText="Name" DataField="name" />
<asp:BoundField HeaderText="Age" DataField="age" />
<asp:TemplateField>
<ItemTemplate>
<asp:Button ID="BtnEdit" runat="server" Text="Edit" />
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
</form>
</body>
</html>
Code Behind
using System;
using System.Collections.Generic;
using System.Web.UI.WebControls;
namespace GridViewDemo
{
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
GridView1.DataSource = GetCustomers();
GridView1.DataBind();
}
protected override void OnInit(EventArgs e)
{
GridView1.RowDataBound += new GridViewRowEventHandler(GridView1_RowDataBound);
base.OnInit(e);
}
void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType != DataControlRowType.DataRow) return;
int age;
if (int.TryParse(e.Row.Cells[1].Text, out age))
if (age == 30)
{
Button btnEdit = (Button) e.Row.FindControl("btnEdit");
btnEdit.Visible = false;
}
}
private static List<Customer> GetCustomers()
{
List<Customer> results = new List<Customer>();
results.Add(new Customer("Steve", 30));
results.Add(new Customer("Brian", 40));
results.Add(new Customer("Dave", 50));
results.Add(new Customer("Bill", 25));
results.Add(new Customer("Rich", 22));
results.Add(new Customer("Bert", 30));
return results;
}
}
public class Customer
{
public string Name {get;set;}
public int Age { get; set; }
public Customer(string name, int age)
{
Name = name;
Age = age;
}
}
}
In the demo, the Edit Button is not Visible (the HTML markup is not sent to the client) in those rows where the Customer's age is 30.
If this was based on roles you could use the multiview panel but not sure if you could do the same against a property of the record.
However, you could do this via code. In your rowdatabound event you can hide or show the button in it.
First, convert your Button/Command Field to a TemplateField, then bind the Visible property of the button to a method that implements the business logic:
<asp:GridView runat="server" ID="GV1" AutoGenerateColumns="false">
<Columns>
<asp:BoundField DataField="Name" HeaderText="Name" />
<asp:BoundField DataField="Age" HeaderText="Age" />
<asp:TemplateField>
<ItemTemplate>
<asp:Button runat="server" Text="Reject"
Visible='<%# IsOverAgeLimit((Decimal)Eval("Age")) %>' />
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
Then, in the code behind, add in the method:
protected Boolean IsOverAgeLimit(Decimal Age) {
return Age > 35M;
}
The advantage here is you can test the IsOverAgeLimit method fairly easily.