SPQuery Index was out of range. Must be non-negative and less than the size of the collection.\r\nParameter name: index

Question

I need to process a query like this

    <Where> 
      <In>
        <FieldRef Name='AgentId' />
        <Values>
           <Value Type='Text'>7727839</Value>
          <Value Type='Text'>222456</Value>
    <Value Type='Text'>0922456</Value>
...


        </Values>
          </In>     
    </Where>

could you please help me to correct my code :

 List<string> conditionsFS = new List<string>();
 private const string CAMLVALUEAGENTID = "<Value Type='Text'>{0}</Value>";
  private const string CAMLWHEREAGENTID = "<Where><In><FieldRef Name='AgentId'/><Values>{0}</Values></In></Where>";
 string conditionFS = string.Format(CAMLVALUEAGENTID, agentId);

                            if (!conditionsFS.Contains(conditionFS))
                            {
                                conditionsFS.Add(conditionFS);
                            }

 string whereFS = string.Format(CAMLWHEREAGENTID, this.BuildConditionsIN(conditionsFS));

 private string BuildConditionsIN(List<string> conditions)
        {
            string conditionStatement = string.Empty;

            if (conditions.Count > 0)
            {
                conditionStatement = "{0}";

                for (int items = conditions.Count; items > 0; items--)
                {
                    string formatedCondition = string.Empty;

                        formatedCondition = conditions[items];


                    conditionStatement = string.Format(conditionStatement, formatedCondition);
                }

            }

            return conditionStatement;
        }

this is the error message from line : " conditionStatement = string.Format(conditionStatement, formatedCondition);" : Index was out of range. Must be non-negative and less than the size of the collection.\r\nParameter name: index

Answer 1

Your for cycle is going in reverse order through the conditions list. In this case you are trying to reference wrong index of the list. In C# lists and arrays are zero-based.

Example. If your conditions list has 3 items, in first step of for loop you are trying to get conditions[3], witch is out of bound.

You should do for loop in normal order like this:

for (int items = 0; items < conditions.Count; items++) 
{
...
}

or fix items value

for (int items = conditions.Count - 1 ; items >= 0; items--)
{
...
}