Search Functionality In ASP.NET GridView

Introduction

Data Grid(GridView), One of the most used data representation format in ASP.NET where data is represented in a tabular format. ASP.NET offers you some basic features to manipulate the GridView elements like Sorting/Paging/Edit/Delete/Update operations. But in some scenarios you might need a searching functionality to implement in the GridView when the loaded data amount is very large (say 500 records).

Lets consider the above case when your GridView has some 500 records and you are searching for a single record then it might be difficult for you to look into all the damn pages of the GridView or/else to look into each record one by one. Are you going to do this ????? No, I am not coz I have a little brain and that's still working.

Behind The Scene

Lets jump into the coding part now...

Its a common notion that while implementing the search functionality we all collect the search data and then call a stored procedure with those parameters and  bind the returned data to the gridview.

But we will not go for calling any stored procedure for this. We will save the data in a session variable while binding the grid for the first time and then will perform all the searching things on it by LINQ.

In this Example we will consider a GridView of  3 columns named 

• ID
• Name
• Email

We need to search the grid according to the above 3 columns. So First design the interface for Search Options.

Lets take a drop down with the above column names and then a text box, where you need to give some input in order to search the grid. And finally a button that has a click event that triggers our code for searching.

These things are upto you. You need to do these things by yourself; Its not a big deal you know it ;)

OK, There may be two scenarios where your datasource is a DataTable or a List :)

When The Data Source Is A List

Hold the list in a session variable first, while binding the GridView for the very first time, that we are going to use later.

  // hold the list in session
  Session["ClaimList"] = listClaim;

Now in the Search button click Event get the list from session variable first.

  // Get the claim list stored in session.
  listClaim = (List<SalesClaim>)Session["ClaimList"];

 Ok that's cool, we have the list in our hand now. Its time to implement search using the LINQ.

Lets take a Switch Case for the above said search columns and use the LINQ for filtering.

  switch (ddlSearch.SelectedValue)
     {
         case "ID": // Filter By ID 
             listClaim = listClaim.Where(p => p.ID.Equals(txtSearch.Text.Trim())).ToList();
             break;
         case "Name": // By Name
             listClaim = listClaim.Where(p => p.Name.ToUpper().Contains(txtSearch.Text.Trim().ToUpper())).ToList();
             break;
         case "Email": // By Email
             listClaim = listClaim.Where(p => p.Email.ToUpper().Contains(txtSearch.Text.Trim().ToUpper())).ToList();
             break;
     }

* ddlSearch is the filtering dropdown we have discussed above with the item values such as ID, 
   Name and Email
* txtSearch is the text box where the search text has to be entered.
* Trim() function is used to remove unwanted white spaces from the search text.
* ToUpper() function is used to convert text to upper case.

Up to this we are all done for searching the list, now bind the gridview and set the session variable again for further use.

   // Bind the grid view
   grdUser.DataSource = listClaim;
   grdUser.DataBind();
   grdUser.EmptyDataText = "No data found";

   // Set the list in session.
   Session["ClaimList"] = listClaim; 

 That's all for the List data source. And lets see how to do this if data source is a DataTable

When The Data Source Is A DataTable

Everything will be same as above except the LINQ. Here store the data table in session while binding the GridView for the very first time.

  // hold the list in session
  Session["ClaimTable"] = dt;

 Now in the Search button click Event get the list from session variable first.

  // Get the claim list stored in session.
  dt= (DataTable)Session["ClaimTable"];

 Ok that's cool, we have the list in our hand now. Its time to implement search using the LINQ.

Lets take a Switch Case for the above said search columns and use the LINQ for filtering.

   // hold the dropdown value in a variable
   string searchColumn = ddlSearch.SelecetedValue;
   
   // hold the search text entered in a variable
   string searchText = txtSearch.Text.Trim();

  Now lets apply LINQ to the DataTable.

   var result = (from myRow in dt.AsEnumerable()
       where myRow.Field<string>(searchColumn ).Equals(searchText)
       select myRow).AsDataView();

 Up to this we are all done for searching the list, now bind the gridview and set the session variable again for further use.

   // Bind the grid view
   grdUser.DataSource = result;
   grdUser.DataBind();
   grdUser.EmptyDataText = "No data found";

   // Set the list in session.
   Session["ClaimList"] = listClaim; 

That's it we have done everything to implement searching functionality in the ASP.NET GridView.

Happy Coding...