Question

我必须将应用程序从Windows窗体移植到ASP.net

一切正常，直到我尝试使用其他表单将销售数据添加到表单中。在Windows窗体中它工作正常，但是当我在ASP中尝试它时，我得到“Null引用异常被用户代码取消了

当我尝试从我的主表单访问“添加新销售”时，会弹出。

我的“添加销售表单”中的代码是：

public partial class AddSaleForm : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }

    public Sale GetData()
    {

        return new Sale(IdTextbox.Text, DateTextbox.Text, LocationTextBox.Text, Convert.ToDouble(PitchCostTextbox.Text), Convert.ToInt32(NumPitchesTextbox.Text), CharityCheckbox.Checked, CharityNameTextbox.Text, CateringCheckBox.Checked);
    }

知道出了什么问题，我在哪里可以解决它？

这是构造函数：

    namespace AntiqueSale
{
    [Serializable]
    public class Sale : IComparable<Sale>
    {
        private String saleId;

        public String SaleId
        {
          get { return saleId; }
          set { saleId = value; }
        }

        private String saleDate;
        private String location;
        private double pitchCost;
        private int numPitches;
        private bool charity;

        public bool Charity
        {
            get { return charity; }
            set { charity = value; }
        }

        private String charityName;
        private bool catering;

        public Sale(String saleId,
                        String saleDate,
                        String location,
                        double pitchCost,
                        int numPitches,
                        bool charity,
                        String charityName,
                        bool catering)
        {
            this.saleId = saleId;
            this.saleDate = saleDate;
            this.location = location;
            this.pitchCost = pitchCost;
            this.numPitches = numPitches;
            this.charity = charity;
            this.charityName = charityName;
            this.catering = catering;
        }

        public override string ToString()
        {
            String str;

            String charityString;
            String cateringString;
            String charityNameString;

            if (charity)
            {
                charityString = "Yes";
                charityNameString = charityName;
            }
            else
            {
                charityString = "No";
                charityNameString = "N/A";
            }

            if (catering)
            {
                cateringString = "Yes";
            }
            else
            {
                cateringString = "No";
            }

            str = String.Format("{0}: {1}: {2}: {3}: {4}: {5}: {6}: {7}",
                                    saleId,
                                    saleDate,
                                    location,
                                    pitchCost,
                                    numPitches,
                                    charityString,
                                    charityNameString,
                                    cateringString);
            return str;
        }

        public int CompareTo(Sale sale)
        {
            return this.SaleId.CompareTo(sale.SaleId);
        }
    }

构造函数不是我设计的，这是我收到的启动代码，我需要修改为asp。

Answer 1

您的问题是以下两行代码之一：

通过执行此操作，验证行PitchCostTextbox.Text中的Convert.ToDouble(PitchCostTextbox.Text)不为空或为空：

double PitchCost = 0.0;
if(!String.IsNullOrEmpty(PitchCostTextbox.Text))
{
    PitchCost = Convert.ToDouble(PitchCostTextbox.Text);
}

确认NumPitchesTextbox.Text行中Convert.ToInt32(NumPitchesTextbox.Text)不为空或为空。

int NumPitches = 0;
if(!String.IsNullOrEmpty(NumPitchesTextbox.Text))
{
    NumPitches = Convert.ToInt32(NumPitchesTextbox.Text);
}

ASP.net中的空引用异常错误

1 个答案: