用户代码未处理NullReferanceException [英] NullReferanceException was unhandled by usercode

查看：64 发布时间：2019/6/18 18:52:12 wpf

本文介绍了用户代码未处理NullReferanceException的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

hii

我陷入了nullreferanceexception错误的错误，用户代码未处理

i m stuck with the error of nullreferanceexception error was unhandled by user code

帮我解决这个问题.

xaml:

< Grid x:Name =" grid_AdminData"保证金="1,4,1,0">
                             < Grid.RowDefinitions>
                    < RowDefinition/>
                    < RowDefinition/>
                    < RowDefinition/>
                    < RowDefinition/>
                    < RowDefinition/>
                    < RowDefinition/>
                    < RowDefinition/>
                    < RowDefinition/>
                    < RowDefinition/>
                             </Grid.RowDefinitions>
                             < Grid.ColumnDefinitions>
                    < ColumnDefinition/>
                    < ColumnDefinition/>
                    < ColumnDefinition/>
                    < ColumnDefinition/>
                             </Grid.ColumnDefinitions>
                             < Label Content =" AdminID:"; HorizontalAlignment =左" VerticalAlignment =顶部"高度＝"18".填充＝"0,0,5,5".前景＝白色". FontStyle =普通" FontWeight =粗体"； FontFamily ="Times New Roman"；宽度＝"82". FontSize ="14"保证金="1,0,0,0&"/>
                             <标签内容=城市:"； Target ="{Binding ElementName = txtCity}" HorizontalAlignment =左" VerticalAlignment =顶部"高度＝"18". 填充＝"0,0,5,0"；前景＝白色". FontStyle =普通" FontWeight =粗体"； FontFamily ="Times New Roman"；宽度＝"82". FontSize ="14" Grid.Column ="1". Grid.Row ＝"2".保证金="0,1,0,0&"/>
                             <标签内容=全名:" Target ="{Binding ElementName = txtFullName}" HorizontalAlignment =左" VerticalAlignment =顶部" 高度＝"18".填充＝"0,0,5,5".前景＝白色". FontStyle =普通" FontWeight =粗体"； FontFamily ="Times New Roman"；宽度＝"82". FontSize ="14" Grid.Column ="1".保证金="0"/>
                             <标签内容=地址:" HorizontalAlignment =左" VerticalAlignment =顶部"高度＝"18".填充＝"0,0,5,5".前景＝白色". FontStyle =普通" FontWeight =粗体"； FontFamily ="Times New Roman"；宽度＝"71".保证金＝"1,1,0,0"； Grid.Row ＝"2". FontSize ="14"/>
                             <标签内容=状态:"； HorizontalAlignment =左" VerticalAlignment =顶部"高度＝"18".填充＝"0,0,5,5".前景＝白色". FontStyle =普通" FontWeight =粗体"； FontFamily ="Times New Roman"；宽度＝"82". FontSize ="14" Grid.Column ="1". Grid.Row ＝"4".保证金="2,1,0,0"/>
                             <标签内容=邮政编码:" HorizontalAlignment =左" VerticalAlignment =顶部"高度＝"18".填充＝"0,0,5,5".前景＝白色". FontStyle =普通" FontWeight =粗体"； FontFamily ="Times New Roman"；宽度＝"93". FontSize ="14" Grid.Column ="1". Grid.Row ="6".保证金="0,1,0,0&"/>
                             <标签内容=性别:"； HorizontalAlignment =左" VerticalAlignment =顶部"高度＝"18".填充＝"0,0,5,5".前景＝白色". FontStyle =普通" FontWeight =粗体"； FontFamily ="Times New Roman"；宽度＝"101". FontSize ="14" Grid.Column ="2".保证金="1,0,0,0&"/>
                             <标签内容=电子邮件ID:" HorizontalAlignment =左" VerticalAlignment =顶部"高度＝"18".填充＝"0,0,5,5".前景＝白色". FontStyle =普通" FontWeight =粗体"； FontFamily ="Times New Roman"；宽度＝"82". FontSize ="14" Grid.Column ="2". Grid.Row ＝"2".保证金="1,1,0,0"/>
                             <标签内容=名称:"； HorizontalAlignment =左" VerticalAlignment =顶部"高度＝"18".填充＝"0,0,5,2".前景＝白色". FontStyle =普通" FontWeight =粗体"； FontFamily ="Times New Roman"；宽度＝"101". FontSize ="14" Grid.Column ="2". Grid.Row ＝"4".保证金="1,1,0,0"/>
                             <标签内容=员工照片:" HorizontalAlignment =左" VerticalAlignment =顶部"高度＝"18".填充＝"0,0,5,2". 前景＝白色". FontStyle =普通" FontWeight =粗体"； FontFamily ="Times New Roman"；宽度＝"118". FontSize ="14" Grid.Column ＝"3". Grid.Row ="6".保证金="1,1,0,0"/>
                             <标签内容="用户名:" HorizontalAlignment =左" VerticalAlignment =顶部"高度＝"18".填充＝"0,0,5,2".前景＝白色". FontStyle =普通" FontWeight =粗体"； FontFamily ="Times New Roman"；宽度＝"101". FontSize ="14" Grid.Column ＝"3".保证金="1,0,0,0&"/>
                             <标签内容=密码:"； HorizontalAlignment =左" VerticalAlignment =顶部"高度＝"18".填充＝"0,0,5,2".前景＝白色". FontStyle =普通" FontWeight =粗体"； FontFamily ="Times New Roman"；宽度＝"101". FontSize ="14" Grid.Column ＝"3". Grid.Row ＝"2".保证金="1,1,0,0"/>
                             < Label Content =" ConfirmPassword:" HorizontalAlignment =左" VerticalAlignment =顶部"高度＝"18".填充＝"0,0,5,2". 前景＝白色". FontStyle =普通" FontWeight =粗体"； FontFamily ="Times New Roman"；宽度＝"129". FontSize ="14" Grid.Column ＝"3". Grid.Row ＝"4".保证金="1,1,0,0"/>
                             < TextBox x:Name =" txtID" Grid.Row ＝"1".保证金＝"0,0,45,0&".填充＝"0". FontStyle =普通" FontSize ="14" FontFamily =" Times 新罗马书》 FontWeight ＝"Normal". IsReadOnly ="True"/>
                             < TextBox x:Name =" txtFullName"样式="{StaticResource VallidationTemplate}" Validation.Error =" Validation_Error"
                   文本="{{Binding UpdateSourceTrigger = LostFocus，Path = FullName，ValidatesOnExceptions = True，
                    ValidatesOnDataErrors = true，NotifyOnValidationError = true}" Grid.Row ＝"1".保证金＝"0,1,40,0&". Grid.Column ="1". FontFamily =" Times 新罗马书》 FontSize ="14" FontStyle =普通" FontWeight ＝"Normal".身高="19"/
                             < TextBox x:Name =" txtUserName" Grid.Row ＝"1".保证金＝"0,0,40,0&"； Grid.Column ＝"3". FontFamily ="Times New Roman"； FontSize ="14" FontStyle =普通" FontWeight ＝"Normal". IsReadOnly ="True"/>
                             < TextBox x:Name =" txtDesignation" Grid.Row ="5".保证金＝"0,0,41,0&"； Grid.Column ="2". FontFamily ="Times New Roman"； FontSize ="14" FontStyle =普通" FontWeight =普通"/>
                             < TextBox x:Name =" txtEmpPhoto" Grid.Row ＝"7".保证金＝"0,0,100,0&"； Grid.Column ＝"3". FontFamily ="Times New Roman"； FontSize ="14" FontStyle =普通" FontWeight ＝"Normal". IsReadOnly ="True"/>
                             < RadioButton x:Name =" rbtMale"内容=男性" Grid.Column ="2". Grid.Row ＝"1". FontFamily ="Times New Roman"； FontSize ="14" FontStyle =普通"保证金＝"0,0,113,0&"；前景=白色"/
                             < RadioButton x:Name ="rbtFemale" FontStyle =普通" FontFamily ="Times New Roman"； FontSize ="14" Grid.Column ="2".保证金="63,0,41,0&" Grid.Row ＝"1".内容=女性"前景=白色"/
                             < TextBox x:Name =" txtCity"样式="{StaticResource VallidationTemplate}" Validation.Error =" Validation_Error"
                   文本="{{Binding UpdateSourceTrigger = LostFocus，Path = City，ValidatesOnExceptions = True，
                    ValidatesOnDataErrors = true，NotifyOnValidationError = true}" Grid.Row ＝"3".保证金＝"0,1,40,0&". Grid.Column ="1". FontFamily =" Times 新罗马书》 FontSize ="14" FontStyle =普通" FontWeight ＝"Normal".身高="19"/
                             < TextBox x:Name =" txtState"样式="{StaticResource VallidationTemplate}" Validation.Error =" Validation_Error"
                   文字="{{Binding UpdateSourceTrigger = LostFocus，Path = State，ValidatesOnExceptions = True，
                    ValidatesOnDataErrors = true，NotifyOnValidationError = true}" Grid.Row ="5".保证金＝"0,1,40,18". Grid.Column ="1". FontFamily ="Times New Roman"； FontSize ="14" FontStyle =普通" FontWeight ＝"Normal".高度＝"20". Grid.RowSpan ="2"/>
                             < TextBox x:Name =" txtPostal"样式="{StaticResource VallidationTemplate}" Validation.Error =" Validation_Error"
                   文本="{{Binding UpdateSourceTrigger = LostFocus，Path = PostalCode，ValidatesOnExceptions = True，
                    ValidatesOnDataErrors = true，NotifyOnValidationError = true}" Grid.Row ＝"7".保证金＝"0,0,40,0&"； Grid.Column ="1". FontFamily =" Times 新罗马书》 FontSize ="14" FontStyle =普通" FontWeight =普通"/>
                             < TextBox x:Name =" txtAddress"样式="{StaticResource VallidationTemplate}" Validation.Error =" Validation_Error"
                   文字="{{Binding UpdateSourceTrigger = LostFocus，Path = Address，ValidatesOnExceptions = True，
                    ValidatesOnDataErrors = true，NotifyOnValidationError = true}" Grid.Row ＝"3".保证金＝"0,1,45,1". Grid.RowSpan ＝"5". FontFamily ="Times New Roman"； FontSize ="14" FontStyle =普通" FontWeight ＝"Normal".身高="97"/>
                             < TextBox x:Name =" txtEMail" Grid.Row ＝"3".保证金＝"0,0,41,0&"； Grid.Column ="2". FontSize ="14" FontFamily ="Times New" 罗马" FontStyle =普通" FontWeight =普通"/>
                             <标签内容=移动设备:"； HorizontalAlignment =左" VerticalAlignment =顶部"高度＝"18".填充＝"0,0,5,2".前景＝白色". FontStyle =普通" FontWeight =粗体"； FontFamily ="Times New Roman"；宽度＝"101". FontSize ="14" Grid.Column ="2". Grid.Row ="6".保证金="1,1,0,0"/>
                             < TextBox x:Name =" txtMobile" Grid.Row ＝"7".保证金＝"0,0,41,0&"； Grid.Column ="2". FontFamily ="Times New Roman"； FontSize ="14" FontStyle =普通" FontWeight =普通"/>
                             < PasswordBox HorizontalAlignment =左"； VerticalAlignment =顶部" Grid.Column ＝"3". Grid.Row ＝"3".宽度＝"133".高度="20"/
                             < PasswordBox x:Name =" txt" HorizontalAlignment =左" VerticalAlignment =顶部" Grid.Column ＝"3". Grid.Row ="5".宽度＝"133". 高度＝"20". FontWeight ＝"Normal". FontFamily ="Times New Roman"； FontSize ="14"/>
                             <按钮x:Name =" btnBrowse" Style ="{StaticResource BrowseButtonStyleTemplate}"内容=浏览" HorizontalAlignment =左" VerticalAlignment =顶部" 宽度＝"58". Grid.Column ＝"3". Grid.Row ＝"7".保证金＝"114,0,0,0&"； FontStyle =普通"填充＝"1,0,1,1".点击="btnBrowse_Click"； FontFamily ="Times New Roman"；高度="20"/
           </Grid>

Cs:

命名空间ITA
{
    ///< summary>
    ///AdminMaster.xaml的交互逻辑
    ///</summary>
   公共局部类AdminMaster:Window
    {
       private int _errors = 0;
      私人Person _Person = new Person();

      公共AdminMaster()
       {
           InitializeComponent();
           grid_AdminData.DataContext = _Person;
       }

       public string conn_String =数据源= Dell;初始目录= ITA;用户ID = sa;密码= 12345";

      私有void btnBrowse_Click(对象发送者，RoutedEventArgs e)
       {
           OpenFileDialog ofd = new OpenFileDialog();
          空的< bool> dlgRes = ofd.ShowDialog();
          如果(dlgRes == true)
           {
                             txtEmpPhoto.Text = ofd.FileName;
           }
       }

      私有void Validation_Error(对象发送者，ValidationErrorEventArgs e)
       {
          如果(e.Action == ValidationErrorEventAction.Added)
                             _errors ++;
          其他
                             _errors--;
       }
    }
}

namespace ITA
{
    /// <summary>
    /// Interaction logic for AdminMaster.xaml
    /// </summary>
    public partial class AdminMaster : Window
    {
        private int _errors = 0;
        private Person _Person = new Person();

        public AdminMaster()
        {
            InitializeComponent();
            grid_AdminData.DataContext = _Person;
        }

        public string conn_String = "Data Source=Dell;Initial Catalog=ITA;User ID=sa;Password=12345";

        private void btnBrowse_Click(object sender, RoutedEventArgs e)
        {
            OpenFileDialog ofd = new OpenFileDialog();
            Nullable<bool> dlgRes = ofd.ShowDialog();
            if (dlgRes == true)
            {
                txtEmpPhoto.Text = ofd.FileName;
            }
        }

        private void Validation_Error(object sender, ValidationErrorEventArgs e)
        {
            if (e.Action == ValidationErrorEventAction.Added)
                _errors++;
            else
                _errors--;
        }
    }
}

Class viewmodel

命名空间ITA
{
   公共类Person:IDataErrorInfo，INotifyPropertyChanged
    {
      公众人物()
       {

       }
      私有字符串F_Name =";
      公共字符串FullName
       {
          得到
           {
                            返回F_Name;
           }
          设置
           {
                            如果(F_Name！=值)
                             {
                    F_Name =值;
                    OnPropertyChanged("FullName");
                             }
           }
       }
      私有字符串_City =";
      公共字符串城市
       {
          得到
           {
                            返回_City;
           }
          设置
           {
                            如果(_City！=值)
                             {
                    _City =值;
                    OnPropertyChanged("City");
                             }
           }
       }
      私有字符串_State =";
      公共字符串State
       {
          得到
           {
                            返回_State;
           }
          设置
           {
                            如果(_State！=值)
                             {
                    _State =值;
                    OnPropertyChanged("State");
                             }
           }
       }
      私有字符串P_Code;
      公共字符串PostalCode
       {
          得到
           {
                            返回P_Code;
           }
          设置
           {
                            如果(P_Code！=值)
                             {
                    P_Code =值;
                    OnPropertyChanged("PostalCode");
                             }
           }
       }
      私有字符串_Address;
      公共字符串地址
       {
          得到
           {
                            返回_Address;
           }
          设置
           {
                            如果(_Address！=值)
                             {
                    _Address =值;
                    OnPropertyChanged("Address");
                             }
           }
       }
      公共事件PropertyChangedEventHandler PropertyChanged;
      受保护的void OnPropertyChanged(string propertyName)
       {
          如果(PropertyChanged！= null)
           {
                             PropertyChanged(this，new PropertyChangedEventArgs(propertyName));
           }
       }

      公共字符串错误
       {
          得到{抛出新的NotImplementedException(); }
       }

      公共字符串this [string columnName]
       {
          得到
           {
                            字符串结果=";
                             //string charVal = @" ^ [a-zA-Z] * $";;
                            字符串txtVal = @" ^ [a-zA-Z] * \ s [a-zA-Z] * \ s [a-zA-Z] * \ s $;
                            字符串numVal = @" [0-9];
                            字符串ScharVal = @"[！|"" | _ | @ |#| \ $ |％| \?| \> | \< | \ * | \ {| \} | \\] | \ [ | \:| \; | \'| \/| \.| \，| \ + | \ = | $| $| \-];
                            字符串mailVal = @" ^(((([\ w] + \.[\ w] +)+)|([\ w] +))@(([[ww ++.)+)([A -Za-z] {1,3})$" ;;

                            如果(FullName.Length！= 0&&！Regex.IsMatch(FullName，txtVal))
                             {
                    result ="输入全名，例如\ n LastName-FirstName-MiddleName"
                             }
                            如果(Regex.IsMatch(FullName，numVal)|| Regex.IsMatch(FullName，ScharVal))
                             {
                    result =输入正确的全名";
                             }
                             if(Regex.IsMatch(City，numVal)|| Regex.IsMatch(City，ScharVal))
                             {
                   结果=输入正确的城市";
                             }
                             if(Regex.IsMatch(State，numVal)|| Regex.IsMatch(State，ScharVal))
                             {
                   结果=进入适当状态";
                             }
                             if(Regex.IsMatch(PostalCode，charVal)|| Regex.IsMatch(PostalCode，ScharVal))
                             {
                                      结果=输入正确的邮政编码";
                             }
                             if(Address.Length！= 0&& Address.Length< 1 || Address.Length> 50)//在这里，我得到了nullreferanceexception的错误未由用户代码处理
                             {
                   结果=输入最多50个单词";
                             }
                            返回结果；
           }
       }
    }
}

namespace ITA
{
    public class Person : IDataErrorInfo, INotifyPropertyChanged
    {
        public Person()
        {

        }
        private string F_Name = "";
        public string FullName
        {
            get
            {
                return F_Name;
            }
            set
            {
                if (F_Name != value)
                {
                    F_Name = value;
                    OnPropertyChanged("FullName");
                }
            }
        }
        private string _City = "";
        public string City
        {
            get
            {
                return _City;
            }
            set
            {
                if (_City != value)
                {
                    _City = value;
                    OnPropertyChanged("City");
                }
            }
        }
        private string _State = "";
        public string State
        {
            get
            {
                return _State;
            }
            set
            {
                if (_State != value)
                {
                    _State = value;
                    OnPropertyChanged("State");
                }
            }
        }
        private string P_Code;
        public string PostalCode
        {
            get
            {
                return P_Code;
            }
            set
            {
                if (P_Code != value)
                {
                    P_Code = value;
                    OnPropertyChanged("PostalCode");
                }
            }
        }
        private string _Address;
        public string Address
        {
            get
            {
                return _Address;
            }
            set
            {
                if (_Address != value)
                {
                    _Address = value;
                    OnPropertyChanged("Address");
                }
            }
        }
        public event PropertyChangedEventHandler PropertyChanged;
        protected void OnPropertyChanged(string propertyName)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }

        public string Error
        {
            get { throw new NotImplementedException(); }
        }

        public string this[string columnName]
        {
            get
            {
                string result = "";
                //string charVal = @"^[a-zA-Z]*$";
                string txtVal = @"^[a-zA-Z]*\s[a-zA-Z]*\s[a-zA-Z]*\s$";
                string numVal = @"[0-9]";
                string ScharVal = @"[!|""|_|@|#|\$|%|\?|\>|\<|\*|\{|\}|\]|\[|\:|\;|\'|\/|\.|\,|\+|\=|$|$|\-]";
                string mailVal = @"^((([\w]+\.[\w]+)+)|([\w]+))@(([\w]+\.)+)([A-Za-z]{1,3})$";

                if (FullName.Length != 0 && !Regex.IsMatch(FullName, txtVal))
                {
                    result = "Enter Full Name like\n LastName - FirstName - MiddleName ";
                }
                if (Regex.IsMatch(FullName, numVal) || Regex.IsMatch(FullName, ScharVal))
                {
                    result = "Enter Proper Full Name";
                }
                if (Regex.IsMatch(City, numVal) || Regex.IsMatch(City, ScharVal))
                {
                    result = "Enter Proper City";
                }
                if (Regex.IsMatch(State, numVal) || Regex.IsMatch(State, ScharVal))
                {
                    result = "Enter proper State";
                }
                if (Regex.IsMatch(PostalCode, charVal) || Regex.IsMatch(PostalCode, ScharVal))
                {
                    result = "Enter Proper PostalCode";
                }
                if (Address.Length != 0 && Address.Length < 1 || Address.Length > 50) // here i got this error of nullreferanceexception was unhandled by usercode
                {
                    result = "Enter maximium 50 words";
                }
                return result;
            }
        }
    }
}

用户代码未处理NullReferanceException [英] NullReferanceException was unhandled by usercode

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用户代码未处理NullReferanceException [英] NullReferanceException was unhandled by usercode

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