Problem With the logic to fill data-table according to given condition

I would create a class to handle this... However I do have one question, in the original table the dates seem... odd you have a start and end date along with the month, start and enddate would be more useful as your december is actually in 2008.

Given the following Class:

//Datatable to edit
DataTable ContributionInfo = new DataTable();

//Entry Point
public FiscalYear()
{
    SetupFiscalDataTable();
}

//Table Setup operations
private void SetupFiscalDataTable()
{
    ContributionInfo.Clear();
    ContributionInfo.Columns.Clear();
    ContributionInfo.Columns.Add("Month");
    ContributionInfo.Columns.Add("Fiscal");
    ContributionInfo.Columns.Add("Name");
    ContributionInfo.Columns.Add("Value");

    DataRow tmpRow = ContributionInfo.NewRow();
    tmpRow["Month"] = 1;
    tmpRow["Fiscal"] = 10;
    tmpRow["Name"] = "January";
    tmpRow["Value"] = 0;
    ContributionInfo.Rows.Add(tmpRow);

    DataRow tmpRow2 = ContributionInfo.NewRow();
    tmpRow2["Month"] = 2;
    tmpRow2["Fiscal"] = 11;
    tmpRow2["Name"] = "February";
    tmpRow["Value"] = 0;
    ContributionInfo.Rows.Add(tmpRow2);

    DataRow tmpRow3 = ContributionInfo.NewRow();
    tmpRow3["Month"] = 3;
    tmpRow3["Fiscal"] = 12;
    tmpRow3["Name"] = "March";
    tmpRow["Value"] = 0;
    ContributionInfo.Rows.Add(tmpRow3);

    DataRow tmpRow4 = ContributionInfo.NewRow();
    tmpRow4["Month"] = 4;
    tmpRow4["Fiscal"] = 1;
    tmpRow4["Name"] = "April";
    tmpRow["Value"] = 0;
    ContributionInfo.Rows.Add(tmpRow4);

    DataRow tmpRow5 = ContributionInfo.NewRow();
    tmpRow5["Month"] = 5;
    tmpRow5["Fiscal"] = 2;
    tmpRow5["Name"] = "May";
    tmpRow["Value"] = 0;
    ContributionInfo.Rows.Add(tmpRow5);

    DataRow tmpRow6 = ContributionInfo.NewRow();
    tmpRow6["Month"] = 6;
    tmpRow6["Fiscal"] = 3;
    tmpRow6["Name"] = "June";
    tmpRow["Value"] = 0;
    ContributionInfo.Rows.Add(tmpRow6);

    DataRow tmpRow7 = ContributionInfo.NewRow();
    tmpRow7["Month"] = 7;
    tmpRow7["Fiscal"] = 4;
    tmpRow7["Name"] = "July";
    tmpRow["Value"] = 0;
    ContributionInfo.Rows.Add(tmpRow7);

    DataRow tmpRow8 = ContributionInfo.NewRow();
    tmpRow8["Month"] = 8;
    tmpRow8["Fiscal"] = 5;
    tmpRow8["Name"] = "August";
    tmpRow["Value"] = 0;
    ContributionInfo.Rows.Add(tmpRow8);

    DataRow tmpRow9 = ContributionInfo.NewRow();
    tmpRow9["Month"] = 9;
    tmpRow9["Fiscal"] = 6;
    tmpRow9["Name"] = "September";
    tmpRow["Value"] = 0;
    ContributionInfo.Rows.Add(tmpRow9);

    DataRow tmpRow10 = ContributionInfo.NewRow();
    tmpRow10["Month"] = 10;
    tmpRow10["Fiscal"] = 7;
    tmpRow10["Name"] = "October";
    tmpRow["Value"] = 0;
    ContributionInfo.Rows.Add(tmpRow10);

    DataRow tmpRow11 = ContributionInfo.NewRow();
    tmpRow11["Month"] = 11;
    tmpRow11["Fiscal"] = 8;
    tmpRow11["Name"] = "November";
    tmpRow["Value"] = 0;
    ContributionInfo.Rows.Add(tmpRow11);

    DataRow tmpRow12 = ContributionInfo.NewRow();
    tmpRow12["Month"] = 12;
    tmpRow12["Fiscal"] = 9;
    tmpRow12["Name"] = "December";
    tmpRow["Value"] = 0;
    ContributionInfo.Rows.Add(tmpRow12);
}
private void ReSetupFiscalDataTable()
{
    for (int i = 0; i < ContributionInfo.Rows.Count; i++)
    {
        ContributionInfo.Rows[i]["Value"] = 0;
    }
}

//Returns Fiscal Year calculation
public DataTable GetFiscalDate(int sFiscalYear, DataTable sSentInfo)
{
    string filterExp;
    string sortExp;


    for (int i = 0; i < ContributionInfo.Rows.Count; i++)
    {
        int tmpContribution = 0;
        int tmpMonth = Convert.ToInt16(ContributionInfo.Rows[i]["Month"]);
        int tmpYear = sFiscalYear;
        if (i <= 2) { tmpYear = sFiscalYear + 1; } //Jan - Mar will be in next year

        filterExp = "'" + tmpMonth + "/2/" + tmpYear + "' > startdate and '" + tmpMonth + "/2/" + tmpYear + "' < enddate";
        sortExp = "startdate";
        DataRow[] tmpMonthtable;
        tmpMonthtable = sSentInfo.Select(filterExp, sortExp);
        for (int z = 0; z < tmpMonthtable.Length; z++)
        {
            tmpContribution += Convert.ToInt16(tmpMonthtable[z][0]);
        }

        ContributionInfo.Rows[i]["Value"] = tmpContribution;
    }

    return ContributionInfo;
}
//Returns True Year calculation
public DataTable GetTrueDate(int sTrueYear, DataTable sSentInfo)
{
    string filterExp;
    string sortExp;


    for (int i = 0; i < ContributionInfo.Rows.Count; i++)
    {
        int tmpContribution = 0;
        int tmpMonth = Convert.ToInt16(ContributionInfo.Rows[i]["Month"]);
        int tmpYear = sTrueYear;

        filterExp = "'" + tmpMonth + "/2/" + tmpYear + "' > startdate and '" + tmpMonth + "/2/" + tmpYear + "' < enddate";
        sortExp = "startdate";
        DataRow[] tmpMonthtable;
        tmpMonthtable = sSentInfo.Select(filterExp, sortExp);
        for (int z = 0; z < tmpMonthtable.Length; z++)
        {
            tmpContribution += Convert.ToInt16(tmpMonthtable[z][0]);
        }

        ContributionInfo.Rows[i]["Value"] = tmpContribution;
    }

    return ContributionInfo;
}

You could use this class to do two different entry points, one would give you the Fiscal year contributions (ie given a fiscal year of 2009 you would get info from April 2009 to March 2010) and the other would give you the true year Jan-Dec. Also, if you have over lap it would add them up.

The Key bit of code here that you are looking for is this:

filterExp = "'" + tmpMonth + "/2/" + tmpYear + "' > startdate and '" + tmpMonth +         "/2/" + tmpYear + "' < enddate";
sortExp = "startdate";
DataRow[] tmpMonthtable;
tmpMonthtable = sSentInfo.Select(filterExp, sortExp);

This piece will allow you to select rows from your Data Table that are relevant and sort them if you want. Using this on a "for" statement with a row for each month allows you to pull out the contribution for a specific month and apply it however you want.

As a note, this code was modified from a similar project I recently worked on.