C# 如何在多列中应用行筛选器从xml中搜索数据

我可以单独搜索我的网格，但是如何在C中应用带多个参数的行过滤器呢#

下面是我试图在C#on Click事件中搜索的代码

 string FirstName = txtFirstName.Text.Trim();
    string Lastname = txtLastName.Text.Trim();
    string EmployeeID = txtEmployeeID.Text.Trim();
    string Department = txtDepartment.Text.Trim();
    string Application = ddlApplication0.SelectedItem.Text.Trim();
    int sApplication = ddlApplication0.SelectedIndex;
    string Action = ddlAction0.SelectedItem.Text.Trim();
    int iAction = ddlAction0.SelectedIndex;

这是单独工作的

if (table.Rows.Count > 0)
{
    if (!String.IsNullOrEmpty(FirstName))
    {
        table.DefaultView.RowFilter = "FirstName = '" + FirstName + "'";
        table = table.DefaultView.ToTable();
        dsquery = table.DefaultView.ToTable();
    }
    if (!String.IsNullOrEmpty(Lastname))
    {
        table.DefaultView.RowFilter = "Lastname = '" + Lastname + "'";
        table = table.DefaultView.ToTable();
        dsquery = table.DefaultView.ToTable();
    }
    if (!String.IsNullOrEmpty(EmployeeID))
    {
        table.DefaultView.RowFilter = "EmployeeID = '" + EmployeeID + "'";
        table = table.DefaultView.ToTable();
        dsquery = table.DefaultView.ToTable();
    }
    if (!String.IsNullOrEmpty(Department))
    {
        table.DefaultView.RowFilter = "Department = '" + Department + "'";
        table = table.DefaultView.ToTable();
        dsquery = table.DefaultView.ToTable();
    }
    if ((sApplication.ToString() != "0"))
    {
        table.DefaultView.RowFilter = "Application = '" + Application + "'";
        table = table.DefaultView.ToTable();
        dsquery = table.DefaultView.ToTable();
    }
    if ((iAction.ToString() != "0"))
    {
        table.DefaultView.RowFilter = "Action = '" + Action + "'";
        table = table.DefaultView.ToTable();
        dsquery = table.DefaultView.ToTable();
    }
    if (rdInprogress.Checked)
    {

        table.DefaultView.RowFilter = "Status = '" + "New Request" + "'";
        table = table.DefaultView.ToTable();
        dsquery = table.DefaultView.ToTable();
    }
    if (rdnRequestCompleted.Checked)
    {
        table.DefaultView.RowFilter = "Status = '" + "Request Completed" + "'";
        table = table.DefaultView.ToTable();
        dsquery = table.DefaultView.ToTable();
    }

}

现在，如何在C#中多次应用过滤器。所以，若用户填写其中任何一个，搜索将在网格中进行。如何组合它？

可能的重复必须为in where子句设计select查询。