Is there a simple property or method to check whether a row changed or column value has been changed in my grid view. I also want to get the index of modified/changed row
You can add it to the gridview like this
<asp:GridView Name="gridview1" OnRowUpdating="GridViewUpdateEventHandler" />
If I remember correctly there is an abundance of tutorials for gridviews and how to manipulate data.
No, there is no simple property for that. But...
Here is a method for that on MSDN
You'll have to modify it for your data and your control names to verify, but it's all there, straight from the keyboard of Microsoft.
protected bool IsRowModified(GridViewRow r)
{
int currentID;
string currentLastName;
string currentFirstName;
currentID = Convert.ToInt32(GridView1.DataKeys[r.RowIndex].Value);
currentLastName = ((TextBox)r.FindControl("LastNameTextBox")).Text;
currentFirstName = ((TextBox)r.FindControl("FirstNameTextBox")).Text;
System.Data.DataRow row =
originalDataTable.Select(String.Format("EmployeeID = {0}", currentID))[0];
if (!currentLastName.Equals(row["LastName"].ToString())) { return true; }
if (!currentFirstName.Equals(row["FirstName"].ToString())) { return true; }
return false;
}
Related
I'm trying to figure out how to sort a GridView with multiple columns (String, DateTime, Decimal, etc. data-types) which is bound to a generic list of custom objects.
MyObject.vb:
Public Property Id
Public Property Name
Public Property Date
Public Property Amount
MyObjects.aspx.vb:
gridView.DataSource = GetMyObjects()
gridView.DataBind()
Note: GetMyObjects() returns a List of MyObject
Basically, I need to be able to click on the column headers of the grid to sort and reverse sort, and also be able to store the sort direction in ViewState so the direction persists each time I click on a column header.
It seems like I probably need MyObject to implement IComparable, but I'm not sure quite how to put it all together.
Can anyone suggest a good tutorial for this, or point me in the right direction?
You need to enable sorting (AllowSorting) and handle the event OnSorting.
Note: The sample code uses C#, but the VB version should be similar.
Create your GridView:
<asp:GridView ID="GridView1" runat="server" AllowSorting="True" OnSorting="GridView1_Sorting">
</asp:GridView>
Handle OnSorting:
protected void GridView1_Sorting(object sender, GridViewSortEventArgs e)
{
GridView1.DataSource = GetObjects(e.SortDirection, e.SortExpression);
GridView1.DataBind();
}
GetObjects returns a sorted List<MyObject>. You have to create your own sorting logic here, one alternative could be using Dynamic Linq. If you choose that route, GetObjects could be defined like this: (there are better ways, but this is enough to show the theory)
private List<MyObject> GetObjects(SortDirection sd, string se)
{
// Have we generated data before?
if (SimulatedDB == null)
{
// Create a sample DB
SimulatedDB = new List<MyObject>();
var rnd = new Random();
for (int i = 0; i < 20; i++)
{
var node = new MyObject();
node.Id = i;
node.Name = String.Format("Name {0}", i);
node.CreationDate = DateTime.Now.AddDays(rnd.Next(100));
node.Amount = (rnd.Next(1000) * rnd.NextDouble());
SimulatedDB.Add(node);
}
}
// Return sorted list
if (sd == SortDirection.Ascending)
return SimulatedDB.AsQueryable<MyObject>().OrderBy<MyObject>(se).ToList();
else
return SimulatedDB.AsQueryable<MyObject>().OrderByDescending<MyObject>(se).ToList();
}
Hope it helps.
I'm using a details view and a sqldatasource control to populate it. Every once in a while i get an error message because more than one row is returned. How can I have the data display in a gridview instead if more than one row is returned?
Databind to both and put this in the OnDataBound event or wherever appropriate in your code. (Obviously you'll need to tweak the code for the names of your objects)
if(myDataTable.Rows.Count > 1)
{
myGridView.Visible = true;
myDetailsView.Visible = false;
}
else
{
myGridView.Visible = false;
myDetailsView.Visible = true;
}
Using ASP.NET 3.5 ListView control.
I would like to capture the value of my table id from the currently edited row of a ListView.
A ItemEditing event has been added to the ListView.
The only value available in this event is e.NewItemIndex.
This returns 0 if the first row of the current page of the ListView is being edited.
How do I convert this 0 into the actual table id (label control value)?
I have tried:
table_id = Convert.ToString(ListView1.Items[e.NewEditIndex].FindControl("table_idLabel1"));
Can you use the DataKeyNames property instead of a label? Set the property to the name of the database field that is the key for the table, then do something like this:
table_id = ListView1.DataKeys[e.NewEditIndex].Value.ToString();
Are you sure table_idLabel1 is the correct id?
Also, you may need to look recursively as in Chris's answer. Plus, it looks like your casting the control to a string. You probably want the ID property and not the control itself.
Use FindControlRecursive (from Recursive Page.FindControl). The problem with FindControl is that it only search one layer deep.
private Control FindControlRecursive(Control root, string id)
{
if (root.ID == id)
{
return root;
}
foreach (Control c in root.Controls)
{
Control t = FindControlRecursive(c, id);
if (t != null)
{
return t;
}
}
return null;
}
I want to bind a List to a GridView on a web page, but override the way the property names display via annotation. I thought System.ComponentModel would work, but this doesn't seem to work. Is this only meant for Windows Forms?:
using System.ComponentModel;
namespace MyWebApp
{
public class MyCustomClass
{
[DisplayName("My Column")]
public string MyFirstProperty
{
get { return "value"; }
}
public MyCustomClass() {}
}
Then on the page:
protected void Page_Load(object sender, EventArgs e)
{
IList<MyCustomClass> myCustomClasses = new List<MyCustomClass>
{
new MyCustomClass(),
new MyCustomClass()
};
TestGrid.DataSource = myCustomClasses;
TestGrid.DataBind();
}
This renders with "MyFirstProperty" as the column header rather than "My Column." Isn't this supposed to work?
When using .net 4 or later you can use gridview1.enabledynamicdata(typeof(mytype)). I haven't looked at all the types you can use there but I know the [displayname("somename")] works well but the [browsable(false)] doesn't omit the column from the grid. It looks like a knit one slip one from MS. at least you can easily rename column names and to omit a column I just declare a variable instead of using a property. It has the same effect...
Just by the way, using the designer to create columns is the easy way out but to just show a different column name takes way to much time especially with classes with many fields.
What SirDemon said...
The answer appears to be no, you can't. At least not out of the box.
The System.Web.UI.WebControls.GridView uses reflected property's name:
protected virtual AutoGeneratedField CreateAutoGeneratedColumn(AutoGeneratedFieldProperties fieldProperties)
{
AutoGeneratedField field = new AutoGeneratedField(fieldProperties.DataField);
string name = fieldProperties.Name; //the name comes from a PropertyDescriptor
((IStateManager) field).TrackViewState();
field.HeaderText = name; //<- here's reflected property name
field.SortExpression = name;
field.ReadOnly = fieldProperties.IsReadOnly;
field.DataType = fieldProperties.Type;
return field;
}
While System.Windows.Forms.DataGridView uses DisplayName if available:
public DataGridViewColumn[] GetCollectionOfBoundDataGridViewColumns()
{
...
ArrayList list = new ArrayList();
//props is a collection of PropertyDescriptors
for (int i = 0; i < this.props.Count; i++)
{
if (...)
{
DataGridViewColumn dataGridViewColumnFromType = GetDataGridViewColumnFromType(this.props[i].PropertyType);
...
dataGridViewColumnFromType.Name = this.props[i].Name;
dataGridViewColumnFromType.HeaderText = !string.IsNullOrEmpty(this.props[i].DisplayName) ? this.props[i].DisplayName : this.props[i].Name;
}
}
DataGridViewColumn[] array = new DataGridViewColumn[list.Count];
list.CopyTo(array);
return array;
}
Unfortunately, while you can override the CreateAutoGeneratedColumn, neither the missing DisplayName nor underlying property descriptor gets passed, and you can't override CreateAutoGeneratedColumns (although you could CreateColumns).
This means you'd have to iterate over reflected properties yourself and in some other place.
If all you care about is the header text in GridView, just use the HeaderText property of each field you bind. If you're autogenerating the columns, you just set the HeaderText after you've bound the GridView.
If you want a GridView that takes into account some attribute you placed on the properties of your bound class, I believe you'll need to create your own GridView.
I may be wrong, but I've not seen any ASP.NET Grid from control vendors (at least Telerik , Janus Systems and Infragistics) do that. If you do it, maybe sell the idea to them.
Are you using .net4, what you need to do is to set enabledynamicdata on the grid view to true.
You can do it now on asp.net mvc2. It works just like that
Ive no problems using Javascript to read the rows of a telerik radgrid component im using however I can seem to find anyway to access the row data server side when a postback occurs. Ive spent ages looking for solution but no luck.
Any pointers would be greatly appreciated.
Tony
You might want to look at the DataKeyValues property of the OwnerTableView object, which will let you access a collection of values that represent the fields in a given row. I use it during the EditCommand event handler, since a user of my site is directed to an edit page if they click on the link to edit a row in the grid, and I need to pass along certain info about the given row in the query string.
If this turns out to be what you need, you'll also need to define which fields should be made available through this property. To do that, look at the MasterTableView.DataKeyNames property in the property sheet for the grid. You basically specify a comma-delimited list of field names.
The server-side is the easy part:
GridItemCollection gridRows = TestGrid.Items;
foreach (GridDataItem data in gridRows)
{
ItemClass obj = (ItemClass)data.DataItem;
}
It's the client side part that I don't know! :[
private Int32 GetID()
{
foreach (Telerik.Web.UI.GridDataItem dataItem in radGrid.MasterTableView.Items)
{
if (dataItem.Selected == true)
{
Int32 ID = (Int32)dataItem.GetDataKeyValue("ID");
return ID;
}
}
throw new ArgumentNullException("Id Not found");
}
This is the one that works for me and uses the RadGrid.SelectedItems collection.
protected void LinkButton1_Click(object sender, EventArgs e)
{
List<Guid> OrderIdList = new List<Guid>();
foreach (GridDataItem OrderItem in this.RadGrid1.SelectedItems)
{
OrderIdList.Add(new Guid(OrderItem.GetDataKeyValue("OrderId").ToString()));
}
}
If you correctly created your controls in markup or page init for dynamic controls, then the RadGrid will properly restore state.
You can access the initial values that were loaded from the data source like this example below, provided you told the table view in question to keep the columns around in the data keys.
protected T GetInitialGridData<T>(GridDataItem item, string uniqueColumnName) {
item.ThrowIfNull("item");
uniqueColumnName.ThrowIfNullOrEmpty("uniqueColumnName");
return (T)item.OwnerTableView.DataKeyValues(gridItem.ItemIndex)(columnName);
}
If you are using a dynamic custom template column, and need to get to any values that may now be in their states, you can use:
protected string GetCustomTextBoxValue(GridDataItem item, string controlID) {
item.ThrowIfNull("item");
controlID.ThrowIfNullOrTrimmedEmpty("controlID");
return ((TextBox)item.FindControl(controlID)).Text;
}
private Int32 GetID()
{
foreach (Telerik.Web.UI.GridDataItem dataItem in radGrid.MasterTableView.Items)
{
if (dataItem.Selected == true)
{
// Int32 ID = (Int32)dataItem.GetDataKeyValue("ID");
Int32 ID =Convert.ToInt32(dataItem.GetDataKeyValue("ID"));
return ID;
}
}
}
//this will work