Why GridView RowUpdating Event is not giving the updated values?

Debugger Inside GridView RowUpdating Event

Debugger Inside GridView RowUpdating Event


This is a most common question in Forums. We will find the actual cause, for which the RowUpdating Event behaves abnormal.

Walk Through

  1. Add a GridView in aspx page and define all its required properties and Events.
    <asp:GridView ID="gvTestGrid" runat="server" AutoGenerateColumns="false" 
                  OnRowCancelingEdit="gvTestGrid_RowCancelingEdit"
                  OnRowEditing="gvTestGrid_RowEditing" 
                  OnRowUpdating="gvTestGrid_RowUpdating">
        <Columns>
            <asp:BoundField DataField="Column1" HeaderText="Some Column"/>
            <asp:CommandField ShowEditButton="true" />
        </Columns>
    </asp:GridView>
    
  2. Bind the GridView from back end. For our example, we will bind one DataTable.
    private void BindGrid()
    {
        // Add Column for the DataTable.
        DataTable dt = new DataTable();
        dt.Columns.Add(new DataColumn("Column1"));
    
        // Add Rows to DataTable.
        for (int i = 1; i < 5; i++)
        {
    	    DataRow dr = dt.NewRow();
    	    dr["Column1"] = "Old Value" + i;
    	    dt.Rows.Add(dr);
        }
    
        gvTestGrid.DataSource = dt;
        gvTestGrid.DataBind();
    }
  3. Define the GridView Events for Edit and Update operation.
    protected void gvTestGrid_RowEditing(object sender, GridViewEditEventArgs e)
    {
        //Set the edit index.
        gvTestGrid.EditIndex = e.NewEditIndex;
    
        //Bind data to the GridView control.
        BindGrid();
    }
    
    protected void gvTestGrid_RowUpdating(object sender, GridViewUpdateEventArgs e)
    {
        //Get the new Values.
        GridViewRow row = gvTestGrid.Rows[e.RowIndex];
        string column1Value = ((TextBox)row.Cells[0].Controls[0]).Text;
    
        // Code to update the DataSource.
        //.....
    
        //Reset the edit index.
        gvTestGrid.EditIndex = -1;
    
        //Bind data to the GridView control.
        BindGrid();
    }
    
    protected void gvTestGrid_RowCancelingEdit(object sender, 
                                               GridViewCancelEditEventArgs e)
    {
        //Reset the edit index.
        gvTestGrid.EditIndex = -1;
    
        //Bind data to the GridView control.
        BindGrid();
    }
    
  4. GridView on Browser would look like…

    GridView on Browser

    GridView on Browser

    Now, Let’s Test

    To test the Edit and Update features, let’s click on Edit Button in any Row. We can see that GridView adds TextBoxes in all the cells of that Row immediately. It also shows you Update and Cancel Buttons where it was previously showing Edit Button.
    Let’s do some editing in the cells and click Update Button.

    GridView Cell Showing Updated Value

    GridView Cell Showing Updated Value


    It hits the breakpoint, we have set inside the RowUpdating Event. If we move our mouse on to the variables, which hold the cell values, we can see the old value instead of new updated value (Refer the debugging Screen Shot at the Top). So, we are stuck now, this is the bug.

    What to do now?

    Don’t panic. We need to find out what exactly in code is helping RowUpdating Event to give old values. So, the most wild guess is that, something is causing the Grid to bind again before RowUpdating Event, as we initially did during load.

    If you remember, in Step-2, we did bind the Grid, which is actually called on the Page Load like…

    protected void Page_Load(object sender, EventArgs e)
    {
        BindGrid();
    }
    

    According to the Event Life Cycle, when any Control Event is fired (here Grid RowUpdating), it first goes to Page Load. As it is coming to Page Load, so it calls the Bind method again and re-binds the Grid. Now, it goes to RowUpdating Event, but the updated values are lost because Grid is already reset in Page Load.

    So, How to Resolve?

    IsPostBack() is the answer. We have to check if the Page is posted back or not. If not, then we will bind the Grid.

    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            BindGrid();
        }
    }
    

    Go and Share this with your friends

    This issue sometimes kills time. So, don’t wait, just share with everybody you know, who can understand this. Also provide your valuable feedback here. Thanks for reading.

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Cancel GridView Edit on Escape Key Press

[DEMO] Cancel GridView Edit on Escape KeyPress

[DEMO] Cancel GridView Edit on Escape KeyPress

This is one interesting research resulting a Trick to Cancel the GridView Editing Mode, when you press the Escape Key. Many guys asked this question in forums and those are still unanswered. Let’s learn and explore.

Is there a Logic?

Ofcourse, there is and its really very simple. When GridView Default Edit Button is clicked on a particular Row, it shows one TextBox for each Cell and one Update and Cancel Button. So, we just need to find that Cancel Button and hit its Click Event explicitly, that’s hit.

Seems Simple, but How to?

With the help of jQuery, which always makes a Developer’s life easier.
Okay, let’s click the Edit Button on First Row. You can see one TextBox, Update and Cancel Button appearing on the Row.

First Row in Edit Mode

First Row in Edit Mode


Referring to the generated HTML (following image), we can see that the Cancel Button does not have any Identity (ID) attribute associated with it.

<a href="javascript:__doPostBack('gvTestEscapePress','Cancel$0')">Cancel</a>

First Row Cancel Button Source HTML

First Row Cancel Button Source HTML


So, the only option here is to find the Button which has the Text as “Cancel“.

Using the Code

For GridView Editing

I have added one CommandField for the Edit Button. You can also use AutoGenerateEditButton="true".

<asp:GridView ID="gvTestEscapePress" 
              runat="server" 
              OnRowEditing="gvTestEscapePress_RowEditing"
              OnRowUpdating="gvTestEscapePress_RowUpdating" 
              OnRowCancelingEdit="gvTestEscapePress_RowCancelingEdit">
    <Columns>
        <asp:CommandField ShowEditButton="true" HeaderText="Edit" />
    </Columns>
</asp:GridView>

To handle the Edit, Update and Cancel Events, we have declared the respective Events (OnRowEditing, OnRowUpdating and OnRowCancelingEdit) inside GridView Markup.
Now, let’s define these Events on Code Behind Page.

/// <summary>
/// This Event shows a particular Row in Editing Mode.
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
protected void gvTestEscapePress_RowEditing(object sender, GridViewEditEventArgs e)
{
    // Set the New Edit Index.
    gvTestEscapePress.EditIndex = e.NewEditIndex;

    // Bind data to the GridView control.
    BindGrid();
}

/// <summary>
/// This Event Cancels the Row Editing on Cancel Button Click.
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
protected void gvTestEscapePress_RowCancelingEdit(Object sender, 
                                                         GridViewCancelEditEventArgs e)
{
    // Reset the edit index.
    gvTestEscapePress.EditIndex = -1;

    // Bind data to the GridView control.
    BindGrid();
}

I am not writing the Update Event code here as it is not important in our discussion. You can refer see that Event in the Source Code by Downloading it.

For Escape Key Press

We will use the following code in order to check the Event KeyCode. If that is 27, it would refer to Escape Key.

<script type="text/javascript">
    $(document).keyup(function (e) {
        if (e.keyCode == 27) {
            // Here we will put the Cancel GridView Editing Logic.    
        }
    });
</script>

For Cancelling the GridView Edit Mode

  1. Here we are searching all anchor (a) tags inside the GridView by .find('a').
  2. Then to get only the Cancel Button, we need to filter by Text using .filter(function () { return $(this).text() === "Cancel" }).
  3. Now it is just a matter of clicking the Button by .click(). Before that, I am just showing one message and on .fadeOut() function, I am clicking the Button.
<script type="text/javascript">
    $(document).keyup(function (e) {
        if (e.keyCode == 27) {
            // Find the Generated Cancel Button for the Row in Edit Mode.
            var cancelButton = $('#<%= gvTestEscapePress.ClientID %>')
                               .find('a')
                               .filter(function () { return $(this).text() === "Cancel" });

            // If Cancel Button is found, then show message and click the Cancel Button.
            if (cancelButton != null && cancelButton.length > 0) {
                $("#lblShowMessage")
                .html("You pressed Escape. Cancelling the GridView Edit...")
                .fadeOut(3000, function () {
                    buttonClick(cancelButton[0]);
                });
            }
        }
    });

    // This function fires the Button Click Event.
    function buttonClick(button) {
        button.click();
    }
</script>

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