I'm trying to make an int equal to a certain value if a condition is true.
I'm having trouble getting the bloodtype int from the if statement so it can be applied to my class. I know its probably a simple solution but my brain is fried.
private void btnAddPatient_Click(object sender, RoutedEventArgs e)////Add Patients
{
string name = txtPatientName.Text;
int bloodType,age=30;
DateTime dob;
bool bloodA = rbA.IsChecked.Equals(true);
bool bloodB = rbB.IsChecked.Equals(true);
bool bloodAB = rbAB.IsChecked.Equals(true);
bool blood0 = rb0.IsChecked.Equals(true);
// if (dpDOB.SelectedDate == null || txtPatientName.Text == ""||bloodType==0)
if (dpDOB.SelectedDate == null || txtPatientName.Text == "" || !bloodA || !bloodAB || !bloodB || !blood0)
{
if (txtPatientName.Text == "")
{
MessageBox.Show("Please enter Patient's Name");
}
else if (!bloodA || !bloodAB || !bloodB || !blood0)
{
MessageBox.Show("Please enter patient's blood type");
}
//else if (dpDOB.SelectedDate == null)
//{
// MessageBox.Show("Please select a date");
//}
}
else
if (bloodA)
{
bloodType = 0;
}
else if (bloodB)
{
bloodType = 1;
}
else if (bloodAB)
{
bloodType = 2;
}
else {
bloodType = 3;
dob = dpDOB.SelectedDate.Value;
Patient patient= new Patient(name, age, bloodType);///cant get bloodtype value
MainWindow mainWindow = Owner as MainWindow;
patients.Add(patient);
lstPatients.ItemsSource = null;
lstPatients.ItemsSource = patients;
// this.Close();
}
The place you want the bloodType will only be evaluated if all other conditions fails as you use a if else if structure. Futhermore, you assign it to 3 prior passing it to the constructor of Patient. Therefore, at the moment this code is evaluated, bloodType will be equal to 3.
try something like
int bloodtype = -1;
(or some other value you won't use otherwise). the variable only gets set inside the if else statements, so you can't send it to your Patient class since it doesn't equal anything outside of the conditionals.
You need to invert your bloodType condition and also take your patient creation out from the blood type 3 check block:
private void btnAddPatient_Click(object sender, RoutedEventArgs e)////Add Patients
{
string name = txtPatientName.Text;
int bloodType,age=30;
DateTime dob;
bool bloodA = rbA.IsChecked.Equals(true);
bool bloodB = rbB.IsChecked.Equals(true);
bool bloodAB = rbAB.IsChecked.Equals(true);
bool blood0 = rb0.IsChecked.Equals(true);
var bloodTypeDefined = bloodA || bloodAB || bloodB || blood0;
// if (dpDOB.SelectedDate == null || txtPatientName.Text == ""||bloodType==0)
if (dpDOB.SelectedDate == null || txtPatientName.Text == "" || !bloodTypeDefined)
{
if (txtPatientName.Text == "")
{
MessageBox.Show("Please enter Patient's Name");
}
else if (!bloodTypeDefined)
{
MessageBox.Show("Please enter patient's blood type");
}
//else if (dpDOB.SelectedDate == null)
//{
// MessageBox.Show("Please select a date");
//}
}
else
{
if (bloodA) bloodType = 0;
else if (bloodB) bloodType = 1;
else if (bloodAB) bloodType = 2;
else bloodType = 3;
dob = dpDOB.SelectedDate.Value;
Patient patient= new Patient(name, age, bloodType);///cant get bloodtype value
MainWindow mainWindow = Owner as MainWindow;
patients.Add(patient);
lstPatients.ItemsSource = null;
lstPatients.ItemsSource = patients;
}
// this.Close();
}
Related
I am experiencing an error that I cannot understand, can anyone explain to me what I am miserably doing wrong?
Database Table:
CREATE TABLE "posti_auto_mil" (
"n_posto" TEXT NOT NULL UNIQUE,
"id_utente" INTEGER NOT NULL,
"targa_1" TEXT NOT NULL,
"targa_2" TEXT NOT NULL,
"targa_3" TEXT NOT NULL,
"targa_4" TEXT NOT NULL,
"targa_5" TEXT NOT NULL,
"locazione" TEXT NOT NULL
);
LoadCar.cs
public static bool CheckTarga(int idUtente)
{
using (IDbConnection cnn = new SQLiteConnection(LoadConnectionString()))
{
var output = cnn.Query($"select * from utenti where id = {idUtente}").FirstOrDefault();
if (output != null)
{
var targa = cnn.Query($"select * from posti_auto_mil where id = {idUtente}").FirstOrDefault();
if (targa != null)
{
var checkpresenza = cnn.Query($"select locazione from posti_auto_mil where id_utente = {idUtente} limit 1");
if (checkpresenza.ToString() == "interno")
{
targaicon = 1;
}
else if (checkpresenza.ToString() == "esterno")
{
targaicon = 2;
}
else if (checkpresenza.ToString() == "provvisorio")
{
targaicon = 2;
}
else targaicon = 3;
}
return true;
}
else
{
targaicon = 3;
return false;
}
}
Form1.cs
//Parking
//Visibilità
listView_targheinfo.Items.Clear();
listView_targheinfo.Visible = true;
pictureBox_infobox.Visible = true;
if (Classi.LoadCar.CheckTarga(Int32.Parse(home_textBox_id.Text)) == true)
{
if (Classi.LoadCar.targaicon == 1)
{
pictureBox_infobox.BackgroundImage = global::RegistroAccessi_8Rgt.Properties.Resources.parking_32px_green;
}
else if (Classi.LoadCar.targaicon == 2)
{
pictureBox_infobox.BackgroundImage = global::RegistroAccessi_8Rgt.Properties.Resources.no_parking_32px;
}
else if (Classi.LoadCar.targaicon == 3)
{
pictureBox_infobox.BackgroundImage = global::RegistroAccessi_8Rgt.Properties.Resources.parking_32px_yellow;
}
else
{
pictureBox_infobox.BackgroundImage = global::RegistroAccessi_8Rgt.Properties.Resources.no_parking_32px;
}
}
else
{
pictureBox_infobox.BackgroundImage = global::RegistroAccessi_8Rgt.Properties.Resources.no_parking_32px;
}
Error:
I've done various tests but I don't understand what I'm doing wrong... can someone clarify this for me?
I can do a personnel search in the same way but I can't do it for vehicle number plates.
This is all of the code i have done so far. The system has a listview that has a column header:
subject name | 1st | 2nd | 3rd | 4th | Final Grades
If the column 1st to 4th contains value it will compute for the final grade of the student. sum(1st to 4th) / 4 *50 + 50. if one of the column does not have a value then the user will be prompted and no final grades will be computed.
I am confused on how do i get all the listview value from 1st to 4th then automatically computes the final grade.
PLease help
private void button1_Click(object sender, EventArgs e)
{
flag = false;
if (txt_numValue.Text != "")
{
char[] entereddata = txt_numValue.Text.ToCharArray();
foreach (char aChar in entereddata.AsEnumerable())
{
if (!Char.IsDigit(aChar))
{
MessageBox.Show("Please enter only numbers.", "In the field Numeric Value");
flag = true;
break;
}
}
}
else if (txt_numValue.Text == "")
{
MessageBox.Show("Please do not leave the field, 'Numeric Value', blank.", "Attention!");
flag = true;
}
if (flag == false)
{
string period = txt_gradingPeriod.Text;
string numeric = txt_numValue.Text;
int cell = 0;
if (period == "1st") { cell = 1; }
else if (period == "2nd") { cell = 2; }
else if (period == "3rd") { cell = 3; }
else if (period == "4th") { cell = 4; }
foreach (ColumnHeader header in listView1.Columns)
{
if (header.Text == period)
{
listView1.Items[0].SubItems[cell].Text = numeric;
break;
}
}
}
}
Once you have got all the data in your list view you can do something like this,
int sum = 0;
foreach (ListViewItem v in listView1.Items)
{
bool hasBlank = false;
for (int i = 0; i < v.SubItems.Count;i++ )
{
if (v.SubItems[i].Text == null || v.SubItems[i].Text == string.Empty)
{
//code
hasBlank = true;
break;
}
else
{
sum += Convert.ToInt16(v.SubItems[i].Text);
}
}
if (!hasBlank)
{
string grade="something";
//formula to calculate grade based on sum.set the result to string grade
v.SubItems[4].Text = grade;
}
else
{
v.SubItems[4].Text = "has blank";
}
sum = 0;
}
This will fill grade if all values are present else a message that it has a blank value.
I am trying to use mod division to determine whether a year in a loop is a census or election year, and I have two issues:
1. I cannot get the wording in line with the year for ex:
It is like:
2000
this is an election year
this is a census year
2001
but I need it to say:
2000, this is an election year, this is a census year
2001 etc
2 : My math is some sort of wrong but I am having trouble identifying why or where, the division needs to apply to a user entered year range, and it needs to divide each year by 10, or 4, and the years that have no remainder are election or census years, but it is not doing that properly, it is not dividing all of the years, just some. My code is this:
private void buttonGo_Click(object sender, EventArgs e)
{
//Variables
int startYr = 0;
int endYr = 0;
int yearDisp = 0;
//Input Validation
startYr = int.Parse(textBoxStartYr.Text);
endYr = int.Parse(textBoxEndYr.Text);
if (int.TryParse(textBoxStartYr.Text, out startYr))
{
//correct
}
else
{
MessageBox.Show("Please enter a four digit year");
return;
}
if (int.TryParse(textBoxEndYr.Text, out endYr))
{
//correct
}
else
{
MessageBox.Show("Please enter a four digit year");
return;
}
//Loop
for (yearDisp = startYr; yearDisp <= endYr; yearDisp++)
{
listBoxDisp.Items.Add("Year:" + yearDisp.ToString());
if (checkBoxCensus.Checked == true )
{
if ((yearDisp % 10) == 0)
{
listBoxDisp.Items.Add("This is a census year");
}
else { }
}
else
{
//nothing needed
}
if (checkBoxElection.Checked == true)
{
if ((yearDisp % 4) == 0)
{
listBoxDisp.Items.Add("This is an election year");
}
else { }
}
else
{
//nothing
}
}
}
Try this:
private void buttonGo_Click(object sender, EventArgs e)
{
// Variables
int startYr = 0;
int endYr = 0;
bool checkForCensus = checkBoxCensus.Checked;
bool checkForElection = checkBoxElection.Checked;
// Input Validation
string errorMsg = "";
if (!int.TryParse(textBoxStartYr.Text, out startYr))
errorMsg += "Please enter a four digit year";
if (!int.TryParse(textBoxEndYr.Text, out endYr))\
errorMsg += String.Format("{0}Please enter a four digit year",
errorMsg == "" ? "" : " ");
if (errorMsg != "")
{
MessageBox.Show(errorMsg);
return;
}
// Loop
for (int yearDisp = startYr; yearDisp <= endYr; yearDisp++)
{
bool isCensusYear, isElectionYear;
if (checkForCensus && (yearDisp % 10) == 0)
isCensusYear = true;
if (checkForElection && (yearDisp % 4) == 0)
isElectionYear = true;
listBoxDisp.Items.Add(String.Format("{0}: {1}{2}{3}",
yearDisp.ToString(),
isCensusYear ? "this is a census year" : "",
(isCensusYear && isElectionYear) ? "," : "",
isElectionYear ? "this is an election year" : ""
));
}
}
Notes:
The empty if and else statements are unnecessary. I have removed the to make them more concise.
On the topic of conditionals in if statements: the ! means "not" or "the opposite of". Examples: !false == true and !true == false.
You do not need the initial int.Parse() statements because TryParse()'s second parameter is an out parameter (it outputs the parsed integer).
I created two variables which get the value of the check box. That way you don't have to check the value every time the loop is executed.
I used a ternary operator and String.Format() to determine what text to display.
Although you didn't mention it, I did change the input validation so that only one message box is displayed.
Try this for your listbox issue.
for (yearDisp = startYr; yearDisp <= endYr; yearDisp++)
{
int index = listBoxDisp.Items.Add("Year:" + yearDisp.ToString());
if (checkBoxCensus.Checked == true)
{
if ((yearDisp % 10) == 0)
{
listBoxDisp.Items[index] += ",This is a census year";
}
else { }
}
else
{
//nothing needed
}
if (checkBoxElection.Checked == true)
{
if ((yearDisp % 4) == 0)
{
listBoxDisp.Items[index] += ",This is an election year";
}
else { }
}
else
{
//nothing
}
}
Try something like this:
private void buttonGo_Click(object sender, EventArgs e)
{
//Variables
int startYr = 0;
int endYr = 0;
int yearDisp = 0;
//Input Validation
if (!int.TryParse(textBoxStartYr.Text, out startYr))
{
MessageBox.Show("Please enter a four digit year");
return;
}
if (!int.TryParse(textBoxEndYr.Text, out endYr))
{
MessageBox.Show("Please enter a four digit year");
return;
}
//Loop
for (yearDisp = startYr; yearDisp <= endYr; yearDisp++)
{
bool isElection = 0 == (yearDisp % 4);
bool isCensus = 0 == (yearDisp % 10);
if (isCensus && checkBoxCensus.Checked && isElection && checkBoxElection.Checked)
{
listBoxDisp.Items.Add(String.Format("{0} This is a both a census year and an election year", yearDisp));
}
else if (isCensus && checkBoxCensus.Checked)
{
listBoxDisp.Items.Add(String.Format("{0} This is a census year", yearDisp));
}
else if (isElection && checkBoxElection.Checked)
{
listBoxDisp.Items.Add(String.Format("{0} This is an election year", yearDisp));
}
else {
listBoxDisp.Items.Add(yearDisp.ToString());
}
}
}
Here's a more concise version of the for loop:
for (yearDisp = startYr; yearDisp <= endYr; yearDisp++)
{
bool isElection = (0 == (yearDisp % 4)) && checkBoxCensus.Checked;
bool isCensus = 0 == (yearDisp % 10) && checkBoxElection.Checked;
string text = yearDisp.ToString();
if (isCensus && isElection)
{
text += " This is a both a census year and an election year";
}
else if (isCensus)
{
text += " This is a census year", yearDisp;
}
else if (isElection)
{
text += " This is an election year";
}
listBoxDisp.Items.Add(text);
}
This line of (C#) code
if (!currentLap.S1.HasValue)
is giving me
System.NullReferenceException: Object reference not set to an instance of an object.
provided I'm sure that currentLap variable is instantiated (because it's being used a few lines before and it is a local variable) and it has following property:
private double? _s1;
[DefaultValue(null)]
[JsonConverter(typeof(ShortDoubleConverter))]
public double? S1
{
get { return _s1; }
set { _s1 = value; }
}
how can it possibly throw NullReferenceException? Can it be something to do with optimization on Release mode?
Thanks,
Stevo
EDIT:
here is full method code.
public void Update(DriverData driverData)
{
LapInfo currentLap = this.CurrentLap;
if (currentLap != null &&
this.LastDriverData != null &&
driverData.TotalLaps != this.LastDriverData.TotalLaps &&
driverData.InPits &&
driverData.Speed < 10 &&
!this.LastDriverData.InPits)
{
currentLap.Escaped = true;
}
this.LastDriverData = driverData;
if ((currentLap == null || currentLap.Lap != driverData.LapNumber) &&
!this.Laps.TryGetValue(driverData.LapNumber, out currentLap))
{
currentLap = new LapInfo() { Lap = driverData.LapNumber, Parent = this, Class = driverData.Class };
this.Laps.Add(driverData.LapNumber, currentLap);
int lapsCount = 0, completedDriverLaps = 0, cleanLaps = 0;
this.TotalLaps = driverData.TotalLaps;
//if it's not the first lap
if (driverData.TotalLaps > 0)
{
//previous lap
if (this.CurrentLap == null || !this.CurrentLap.Escaped)
{
this.CompletedLaps++;
if (this.CurrentLap == null || !this.CurrentLap.MaxIncident.HasValue)
this.CleanLaps++;
}
}
foreach (DriverLapsInfo laps in this.Parent.LapsByVehicle.Values)
{
lapsCount += laps.TotalLaps;
completedDriverLaps += laps.CompletedLaps;
cleanLaps += laps.CleanLaps;
}
this.Parent.Parent.SetLapsCount(driverData, lapsCount, driverData.Class, completedDriverLaps, cleanLaps);
}
this.CurrentLap = currentLap;
//add incidents
if (driverData.Incidents != null)
{
foreach (IncidentScore incident in driverData.Incidents)
{
this.CurrentLap.MaxIncident = Math.Max(this.CurrentLap.MaxIncident ?? 0, incident.Strength);
this.CurrentLap.Incidents++;
this.Incidents++;
}
}
LapInfo previousLap = null;
if ((this.PreviousLap == null || this.PreviousLap.Lap != driverData.TotalLaps) &&
this.Laps.TryGetValue(driverData.TotalLaps, out previousLap))
{
this.PreviousLap = previousLap;
if (!this.PreviousLap.Date.HasValue)
{
this.PreviousLap.Date = DateTime.UtcNow;
}
}
if (currentLap.Position == 0)
currentLap.Position = driverData.Position;
if (driverData.CurrentS1 > 0)
{
**if (!currentLap.S1.HasValue)**
{
this.UpdateBestS1(driverData.BestS1);
this.Parent.Parent.UpdateBestS1(driverData.BestS1, driverData.UniqueName);
currentLap.UpdateS1(driverData.CurrentS1, driverData);
//reset the best split set at the finish line
if (this.PreviousLap != null && this.PreviousLap.SplitBest < 0)
this.PreviousLap.SplitBest = 0;
}
if (driverData.CurrentS2.HasValue && driverData.CurrentS1.HasValue && !currentLap.S2.HasValue)
{
double s2 = driverData.CurrentS2.Value - driverData.CurrentS1.Value;
this.UpdateBestS2(s2);
this.Parent.Parent.UpdateBestS2(s2, driverData.UniqueName);
currentLap.UpdateS2(s2, driverData);
}
}
if (this.PreviousLap != null)
{
if (driverData.LastLap > 0)
{
if (!this.PreviousLap.S3.HasValue && driverData.LastS2.HasValue)
{
double s3 = driverData.LastLap.Value - driverData.LastS2.Value;
this.UpdateBestS3(s3);
this.Parent.Parent.UpdateBestS3(s3, driverData.UniqueName);
this.PreviousLap.UpdateS3(s3, driverData);
}
if (!this.PreviousLap.LapTime.HasValue)
{
double? bestLap = this.Parent.Parent.BestLap;
this.PreviousLap.UpdateLapTime(driverData, 0);
this.Parent.Parent.UpdateBestLap(this.PreviousLap, driverData.BestLap, driverData);
this.UpdateBestLap(driverData.BestLap, this.PreviousLap);
this.PreviousLap.UpdateLapTime(driverData, bestLap);
}
}
else
{
if (this.PreviousLap.SplitBest.HasValue)
this.PreviousLap.UpdateBestSplit();
if (this.PreviousLap.SplitSelf.HasValue)
this.PreviousLap.UpdateSelfSplit();
}
}
if (driverData.InPits)
{
switch (driverData.Sector)
{
case Sectors.Sector1:
if (previousLap != null)
previousLap.InPits = true;
break;
case Sectors.Sector3:
currentLap.InPits = true;
break;
}
}
//lap to speed
if (currentLap.TopSpeed < driverData.Speed)
{
driverData.TopSpeedLap = driverData.Speed;
currentLap.UpdateTopSpeed(driverData.Speed);
}
else
driverData.TopSpeedLap = currentLap.TopSpeed;
//overall top speed
if (this.TopSpeed < driverData.Speed)
{
driverData.TopSpeed = driverData.Speed;
this.TopSpeed = driverData.Speed;
this.Parent.Parent.UpdateTopSpeed(this.TopSpeed, driverData);
}
else
driverData.TopSpeed = this.TopSpeed;
}
There is no way on earth the code can make it to that line and currentLap beeing null.
Or am I going crazy? :)
.HasValue will not throw if the nullable reference is null, but a.b.HasValue will if a is null.
I suspect that currentLap == null. I know you say you're sure that currentLap is not null, but I think that's the most likely explanation. Can you post more code?
Update:
Thanks for posting your code.
This doesn't throw:
void Main() {
var f = new Foo();
Console.WriteLine (f.S1);
Console.WriteLine (f.S1.HasValue);
}
class Foo {
private double? _s1 = null;
public double? S1 {
get { return _s1; }
set { _s1 = value; }
}
}
Could you try to create a minimal reproduction? (minimal code that exhibits the issue)
Maybe have a look at the previous line of code :) - debugger often highlights the next line after the one where the NullReferenceException was actually thrown.
My C# code is something like as follows.
if(TextBox1.Text.Length > 5)
{
if(TextBox2.Text.Length > 5)
{
if(TextBox3.Text.Length > 5)
{
if(TextBox4.Text.Length > 5)
{
//Action to pass to the next stage.
}
else
{
error4.text = "Textbox4 value should be minimum of 5 characters.";
}
}
else
{
error3.text = "Textbox3 value should be minimum of 5 characters.";
}
}
else
{
error2.text = "Textbox2 value should be minimum of 5 characters.";
}
}
else
{
error1.text = "Textbox1 value should be minimum of 5 characters.";
}
1) In the above kind of sample. I am using nested If-Else concept where on button click, if TextBox1 value is less than 5 is moves to else part and shows the error1 value but it will not check for further errors.
2) If I change If conditions to step by step If conditions then it will not work for me because the action must be done only if all the IF conditions satisfies.
3) If I use && operator to check all conditions I will not get individual error to each "error label"
How can I check multiple IF conditions on a single button click?
My original code
if (checkavail == "available")
{
if (name.Text.Length > 0)
{
if (email.Text.Length > 5)
{
if (password1.Text.Length > 7 && password1.Text == password2.Text)
{
if (alternate.Text.Contains("#") && alternate.Text.Contains("."))
{
if (question.Text.Length > 0)
{
if (answer.Text.Length > 0)
{
Response.Redirect("next_page.aspx");
}
else
{
error5.Text = "Please enter your security answer";
}
}
else
{
error4.Text = "Please enter your security question";
}
}
else
{
error3.Text = "Invaild alternate email address";
}
}
else
{
error2.Text = "Password should be minimum 8 characters and must match confirm password";
}
}
else
{
error1.Text = "Email address should be minimum 6 characters";
}
}
else
{
error.Text = "Please enter your name";
}
}
else
{
error1.Text = "This email address is already taken. Please try another";
}
I need the Redirect action to be done upon satisfying all conditions. If more than one error was found each error should get each error message.
Make a function that just handles the error messages. Return an Enumerable from this function. Then you can format your if-statements like this and it will return an Enumerable:
private IEnumerable GetErrors()
{
if (TextBox1.Text.Length > 5) { yield return "Textbox1 minimum bla bla"; }
if (TextBox2.Text.Length > 5) { yield return "Textbox2 minimum bla bla"; }
if (TextBox3.Text.Length > 5) { yield return "Textbox3 minimum bla bla"; }
}
Make another function that handles your non-error message logic and just perform an if-statement to see if there were zero errors or not:
public void DoSomething()
{
var errors = GetErrors();
if (errors.Count == 0)
Response.Redirect("next_page.aspx");
else
error.Text = "Please fix your errors";
}
Thanks to all. I found my answer in below manner
string p1, p2, p3, p4;
if (TextBox1.Text.Length > 5)
{
p1 = "pass";
Label1.Text = "";
}
else
{
Label1.Text = "Textbox1 value should be minimum 5 characters.";
p1 = "fail";
}
if (TextBox2.Text.Length > 5)
{
p2 = "pass";
Label2.Text = "";
}
else
{
Label2.Text = "Textbox2 value should be minimum 5 characters.";
p2 = "fail";
}
if (TextBox3.Text.Length > 5)
{
p3 = "pass";
Label3.Text = "";
}
else
{
Label3.Text = "Textbox3 value should be minimum 5 characters.";
p3 = "fail";
}
if (TextBox4.Text.Length > 5)
{
p4 = "pass";
Label4.Text = "";
}
else
{
Label4.Text = "Textbox4 value should be minimum 5 characters.";
p4 = "fail";
}
if (p1 == "pass" && p2 == "pass" && p3 == "pass" && p4 == "pass")
{
Status.Text = "All pass";
}