Selecting first 10 records, then next 10, paging using Linq

var total = dtDetails.Rows.Count;
var pageSize = 10; // set your page size, which is number of records per page

var page = 1; // set current page number, must be >= 1

var skip = pageSize * (page-1);

var canPage = skip < total;

if (canPage) // do what you wish if you can page no further
   return;

DataTable dtFilteredData= dtDetails.AsEnumerable().Skip(skip).Take(pageSize).CopyToDataTable();

How to create C# variables dynamically?

In some cases we have scenario like have to create variables dynamically.To achieve this we have to use dictionary.I have shown some sample example with this post.

Sample variables
String strvar_1=null;
String strvar_2=null;
String strvar_3=null;

strvar_1="DynamicValue_1";
strvar_2="DynamicValue_2";
strvar_3="DynamicValue_3";

//below is the code to dynamically create above variable and assigning the values 

//Create dictionary to create variable names
//In this first string would be the variable name and second string would be the value for that variable we are assigning null initially
Dictionary<String, String> dynstr = new Dictionary<String, String>();
for(int i = 1; i < 4; i++) {
  dynstr .Add("strvar_" + i, null);
  }

//we are assigning value to those variables
  for(int i = 1; i < 4; i++) {
    dogs["strvar_" + i] = "DynamicValue_" + i;
  }

Create Retrieve Update and Delete SharePoint List Item using REST API and JQuery

In this article, it is showed you how to  utilizing SharePoint REST API and JQuery to Create, Retrieve, Update and Delete SharePoint list item.

Pre-Requisite

Reference to latest jquery.min.js
For this example purposes, create custom List called “MyList” with default “Title” column.
Create

// occurs when a user clicks the create button

function CreateNew() {
    var listName = "MyList";
    var newItemTitle = "New Title Item";
    CreateListItemWithDetails(listName, _spPageContextInfo.webAbsoluteUrl, newItemTitle, function () {
        alert("New Item has been created successfully.");
 }, function () {
     alert("Ooops, an error occured. Please try again.");
 });
}

CREATE Operation

// listName: The name of the list you want to get items from
// weburl: The url of the web that the list is in. 
// newItemTitle: New Item title.
// success: The function to execute if the call is sucesfull
// failure: The function to execute if the call fails

function CreateListItemWithDetails(listName, webUrl, newItemTitle, success, failure) {
    var itemType = GetItemTypeForListName(listName);
    var item = {
        "__metadata": { "type": itemType },
        "Title": newItemTitle
    };

    $.ajax({
        url: _spPageContextInfo.siteAbsoluteUrl + "/_api/web/lists/getbytitle('" + listName + "')/items",
        type: "POST",
        contentType: "application/json;odata=verbose",
        data: JSON.stringify(item),
        headers: {
            "Accept": "application/json;odata=verbose",
            "X-RequestDigest": $("#__REQUESTDIGEST").val()
        },
        success: function (data) {
            success(data);
        },
        error: function (data) {
            failure(data);
        }
    });
}

Get List Item Type metadata

function GetItemTypeForListName(name) {
    return "SP.Data." + name.charAt(0).toUpperCase() + name.split(" ").join("").slice(1) + "ListItem";
}

Retrieve Item

 READ SPECIFIC ITEM operation

// itemId: The id of the item to get
// listName: The name of the list you want to get items from
// siteurl: The url of the site that the list is in. 
// success: The function to execute if the call is sucesfull
// failure: The function to execute if the call fails

function getListItemWithId(itemId, listName, siteurl, success, failure) {
    var url = siteurl + "/_api/web/lists/getbytitle('" + listName + "')/items?$filter=Id eq " + itemId;
    $.ajax({
        url: url,
        method: "GET",
        headers: { "Accept": "application/json; odata=verbose" },
        success: function (data) {
            if (data.d.results.length == 1) {
                success(data.d.results[0]);
            }
            else {
                failure("Multiple results obtained for the specified Id value");
            }
        },
        error: function (data) {
            failure(data);
        }
    });
}


Retrieve All Items

// occurs when a user clicks the read button

function Read() {
    var listName = "MyList";
    var url = _spPageContextInfo.webAbsoluteUrl;

    getListItems(listName, url, function (data) {
        var items = data.d.results;

        // Add all the new items
        for (var i = 0; i < items.length; i++) {
            alert(items[i].Title + ":" + items[i].Id);
        }
    }, function (data) {
        alert("Ooops, an error occured. Please try again");
    });
}

 READ operation

// listName: The name of the list you want to get items from
// siteurl: The url of the site that the list is in. 
// success: The function to execute if the call is sucesfull
// failure: The function to execute if the call fails

function getListItems(listName, siteurl, success, failure) {
    $.ajax({
        url: siteurl + "/_api/web/lists/getbytitle('" + listName + "')/items",
        method: "GET",
        headers: { "Accept": "application/json; odata=verbose" },
        success: function (data) {
            success(data);
        },
        error: function (data) {
            failure(data);
        }
    });
}

Update

// occurs when a user clicks the update button

function Update() {
    var listName = "MyList";
    var url = _spPageContextInfo.webAbsoluteUrl;
    var itemId = "1"; // Update Item Id here
    var title = "New Updated Title";
    updateListItem(itemId, listName, url, title, function () {
        alert("Item updated, refreshing avilable items");
    }, function () {
        alert("Ooops, an error occured. Please try again");
    });
}

Update Operation

/ listName: The name of the list you want to get items from
// siteurl: The url of the site that the list is in. // title: The value of the title field for the new item
// itemId: the id of the item to update
// success: The function to execute if the call is sucesfull
// failure: The function to execute if the call fails

function updateListItem(itemId, listName, siteUrl, title, success, failure) {
    var itemType = GetItemTypeForListName(listName);

    var item = {
        "__metadata": { "type": itemType },
        "Title": title
    };

    getListItemWithId(itemId, listName, siteUrl, function (data) {
        $.ajax({
            url: data.__metadata.uri,
            type: "POST",
            contentType: "application/json;odata=verbose",
            data: JSON.stringify(item),
            headers: {
                "Accept": "application/json;odata=verbose",
                "X-RequestDigest": $("#__REQUESTDIGEST").val(),
                "X-HTTP-Method": "MERGE",
                "If-Match": data.__metadata.etag
            },
            success: function (data) {
                success(data);
            },
            error: function (data) {
                failure(data);
            }
        });
    }, function (data) {
        failure(data);
    });
}


Delete

// occurs when a user clicks the delete button

function Delete() {
    var listName = "MyList";
    var url = _spPageContextInfo.webAbsoluteUrl;
    var itemId = "1"; // Update Item ID here
    deleteListItem(itemId, listName, url, function () {
        alert("Item deleted successfully");
    }, function () {
        alert("Ooops, an error occured. Please try again");
    });
}

// Delete Operation
// itemId: the id of the item to delete
// listName: The name of the list you want to delete the item from
// siteurl: The url of the site that the list is in.
// success: The function to execute if the call is sucesfull
// failure: The function to execute if the call fails
function deleteListItem(itemId, listName, siteUrl, success, failure) {
    getListItemWithId(itemId, listName, siteUrl, function (data) {
        $.ajax({
            url: data.__metadata.uri,
            type: "POST",
            headers: {
                "Accept": "application/json;odata=verbose",
                "X-Http-Method": "DELETE",
                "X-RequestDigest": $("#__REQUESTDIGEST").val(),
                "If-Match": data.__metadata.etag
            },
            success: function (data) {
                success(data);
            },
            error: function (data) {
                failure(data);
            }
        });
    },
   function (data) {
       failure(data);
   });
}


Source url : https://tjendarta.wordpress.com/2014/02/20/create-retrieve-update-and-delete-sharepoint-list-item-using-rest-api-and-jquery/