Data refresh issue in ASP.NET gridview

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5.00/5 (1 vote)

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Hi I am facing a data refresh problem in asp.net.
On the home page when a link is clicked another page is loaded which has a gridview control.This gridview displays data from an xml file and it has edit/update options in it.
When the value of any cell is edited and updated the new value is displayed in the gridview and also successfully written back to the xml in the back end.But the problem is that if the linked is clicked again the grid view shows the old data rather than the updated data.

Can someone please help me out.

What I have tried:

1.I have tried using EnableRowsCache="false"in the aspx file,it didn't help.
2.Tried the below code ,but it causes exception when the edit button in the gridview is clicked

protected void Page_Load(object sender, EventArgs e)
{
    if (IsPostBack)
    {
        MyGridView.DataBind();
    }
}

Posted 22-Sep-16 1:08am

Member 3864348

Updated 22-Sep-16 22:00pm

Suvendu Shekhar Giri

v2

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Comments

Karthik_Mahalingam 22-Sep-16 7:30am

assign the datasource

Member 3864348 22-Sep-16 7:49am

ata();
}
}

And LoadData() has been defined as below:-

protected void LoadData()
{
// Creates a data table and populate it from data from xml file.Have just removed the data table population code to keep this post short.
DataTable dt = new DataTable()
MyGridView.DataSource = dt;
MyGridView.DataBind();
}

So,DatBind() is already called but no luck.
When I click on the link(menu item on the home page) again after I modify the data in the gridview,it still shows the older data (however the data in the backend xml file is being updated)

Karthik_Mahalingam 22-Sep-16 7:52am

place break point and check the datatabe contains data

Member 3864348 22-Sep-16 7:55am

There is no database involved in it,the data being shown in the gridview are from an XML file.

3 solutions

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Suvendu Shekhar Giri · Answer 1 · 2016-09-22T01:15:00

Solution 1

It should be not IsPostback
Check following-

C#

protected void Page_Load(object sender, EventArgs e)
{
   if (!IsPostBack) // note the not operator (!)
   {
      MyGridView.DataBind();
   }
}

Hope, it helps :)

Posted 22-Sep-16 1:15am

Suvendu Shekhar Giri

Comments

Member 3864348 22-Sep-16 7:25am

Hi,
Thanks for you reply.
I already have a method named LoadData() which is getting called as

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

and inside LoadData() method the MyGridView.DataBind() is called.But this has not helped me.

Suvendu Shekhar Giri 22-Sep-16 7:29am

Can you share the relevant code i.e,
--LoadData()
--edit button click event

Member 3864348 22-Sep-16 7:51am

This is how the LoadData() looks

protected void LoadData()
{
// Creates a data table and populate it from data from xml file.have just removed the data table population code to keep this post short.
DataTable dt = new DataTable()
MyGridView.DataSource = dt;
MyGridView.DataBind();
}

Suvendu Shekhar Giri 22-Sep-16 7:54am

This potion looks perfectly fine. Can you also share the link/button click event code?

Member 3864348 22-Sep-16 8:04am

protected void MyGridView_RowUpdating(object sender,GridViewUpdateEventArgs e)
{
TextBox tbProcessName =(TextBox)MyGridView.Rows[e.RowIndex].FindControl("txtProcessName");

TextBox tbStatus = (TextBox)MyGridView.Rows[e.RowIndex].FindControl("txtStatus");

string ModifiedProcessName = tbProcessName.Text;
string ModifiedStatus = tbStatus.Text;

// Then code to write the changed data back to the xml file.

MyGridView.EditIndex = -1;
LoadData();
}

Member 3864348 22-Sep-16 8:07am

I guess the older data are cached somewhere and then when the paged is re-loaded the older data get displayed.

Suvendu Shekhar Giri 22-Sep-16 8:34am

That's possible. Final, I would also like to see how you are getting data from XML to datatable and saving to XML too.

Member 3864348 23-Sep-16 4:01am

I have fixed the issue,it was the cache problem.
Thanks for you help anyways.

Vincent Maverick Durano · Answer 2 · 2016-09-22T01:38:00

Solution 2

You need to set the DataSource before calling DataBind() to reflect the changes.

C#

protected void Page_Load(object sender, EventArgs e)
{
   if (!IsPostBack) 
   {
      MyGridView.DataSource = ???; //set the data source here
      MyGridView.DataBind();
   }
}

Posted 22-Sep-16 1:38am

Vincent Maverick Durano

Comments

Member 3864348 22-Sep-16 7:48am

Hi,

My Page_load() method is as below:-
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
LoadData();
}
}

And LoadData() has been defined as below:-

protected void LoadData()
{
// Creates a data table and populate it from data from xml file.Have just removed the data table population code to keep this post short.
DataTable dt = new DataTable()
MyGridView.DataSource = dt;
MyGridView.DataBind();
}

So,DatBind() is already called but no luck.
When I click on the link(menu item on the home page) again after I modify the data in the gridview,it still shows the older data (however the data in the backend xml file is being updated)

Could you plz help me out.

Vincent Maverick Durano 22-Sep-16 8:55am

I would suggest you to debug your code, set a break point at LoadData() method and then step into it to figure out what went wrong.

Member 3864348 · Answer 3 · 2016-09-22T22:00:00

Solution 3

It was a cache problem indeed.

Calling

C#

Response.Cache.SetCacheability(HttpCacheability.NoCache) in Page_Load() fixed the refresh issue.

Posted 22-Sep-16 22:00pm

Member 3864348