Unable to Read Calendar List Items through CAML

Question

Hi All,
* I have created two columns in calendar one Year and other Month.When new event is added in calendar through (Item Added) event receiver I am setting the values to this columns as Name of Month to(February) and Year as(2014)  .So that I can fetch the
data easily based on month and year
* Through this Columns Secondly when I try to fetch the data to count number of items of particular month and year using caml query I am getting error as below .
"Error:One or more field types are not installed properly. Go to the list settings page to delete these fields."
*My below caml code is working fine if i applied to custom list,But not to calendar.Can any one help me for what reason I am unable to fetch data
Code
 string year="2014";
 string month="February";
 SPSite mysite = SPContext.Current.Site;
 SPWeb myweb = mysite.OpenWeb();
SPList mylist = myweb.Lists["Calendar"];
 SPQuery myquery = new SPQuery();
  myquery.Query = @"<Where>
                                      <And>
                                       <Eq>
                                         <FieldRef Name='Year'/>
                                         <Value Type='Text'>" + year + @"</Value>
                                      </Eq>
                                      <Eq>
                                         <FieldRef Name='Month' />
                                         <Value Type='Text'>" + month + @"</Value>
                                      </Eq>
                                     </And>
                                  </Where>";
 SPListItemCollection totaltiems = mylist.GetItems(myquery);
  Label1.Text= "Total Number of Items is "+" "+totaltiems.Count.ToString();
Thanks, Quality Communication Provides Quality Work. http://siddiq-sharepoint2010.blogspot.in/ Siddiqali Mohammad .

Answer 1

Hi,
According to your post, my understanding is that you got an error when read calendar list items using CAML.
I created two single line of text columns in the Calendar( Year and Month), then add items in the Calendar to check with your code. The CAML query worked well as below.
string year = "2014";
string month = "February";
using (SPSite oSiteCollection = new SPSite("Your site URL"))
using (SPWeb myweb = oSiteCollection.OpenWeb())
SPList mylist = myweb.Lists["Calendar"];
SPQuery myquery = new SPQuery();
myquery.Query = @"<Where> <And> <Eq> <FieldRef Name='Year'/> <Value Type='text'>" + year
+ "</Value></Eq><Eq>+ "
+ " <FieldRef Name='Month' />+ "
+ " <Value Type='text'>" + month + "</Value>+ "
+ " </Eq> </And></Where>";
SPListItemCollection totaltiems = mylist.GetItems(myquery);
Console.WriteLine( "Total Number of Items is " + " " + totaltiems.Count.ToString());
Console.ReadLine();
Which type of the two columns in your Calendar? Were they text type?
Are you sure the field name(<FieldRef Name='Year'/>,
<FieldRef Name='Month' />) is same as internal name?
We should only use internal name while refrencing columns in CAML query. If you have space In you column , replace it with "_x0020_", such as
News_x0020_Category. 
Thanks & Regards,
Jason 
Jason Guo
TechNet Community Support