How to create Dynamic Where Clause in Linq

C# Method:

 public IQueryable GetProductList(string whereClause)
    {
        var query = context.ItemMaster_Stage
                              .Where(whereClause);
  
        return (IQueryable)query;
    }

Method calling:

IQueryable obj = new Products().GetProductList("it.ITEM_NAME == 'WEDDING BANDS'");

Here you can call this method with 'Where' clause as per your requirement.

Linq To Sql return from function as IQueryable

Following is the example illustrating how we can return IQueryable<T> from a method which has linq to SQL statements and bind returned data to a asp.net repeater control:

public IQueryable GetParentCategory()
    {
        return (context.CategoryMaster
           .Where(c => c.PARENT_CATEGORY_ID == 0)
           .Select(c => new { c.PARENT_CATEGORY_ID, c.CATEGORY_NAME, c.CATEGORY_ID })).AsQueryable();
    }

In above example we need only three fields (Projection) from data source.

We can bind repeater with following code:

rptParentCategory.DataSource = new Products().GetParentCategory();
rptParentCategory.DataBind();

Here 'Product' is a class in 'App_code' containing method 'GetParentCategory'.