Set default value in custom control - c#

I am creating custom web control(textbox) which allows only integer data type in textbox.
On button submit event if there is no data in textbox, custom control should set TextBox1.Text=0, this is what i want. This is code which i wrote.
public class MasIntTextBox : TextBox
{
private RequiredFieldValidator req;
private RegularExpressionValidator regex;
public string ValGrp { get; set; }
public string IsRequired { get; set; }//give true/yes or false/no values only
protected override void OnInit(EventArgs e)
{
//this.CssClass = "inp-form";
if (IsRequired == "true" || IsRequired == "yes")
{
req = new RequiredFieldValidator();
req.ControlToValidate = this.ID;
req.ErrorMessage = "Enter Numeric Value";
req.Display = ValidatorDisplay.Dynamic;
if (!string.IsNullOrEmpty(ValGrp))
req.ValidationGroup = ValGrp;
Controls.Add(req);
}
regex = new RegularExpressionValidator();
regex.ControlToValidate = this.ID;
regex.ErrorMessage = "Numeric Value Only";
regex.Display = ValidatorDisplay.Dynamic;
regex.ValidationExpression = "^\\d+(\\.\\d+)?$";
if (!string.IsNullOrEmpty(ValGrp))
regex.ValidationGroup = ValGrp;
Controls.Add(regex);
//base.OnInit(e);
}
protected override void Render(HtmlTextWriter w)
{
base.Render(w);
if (IsRequired == "true" || IsRequired == "yes")
req.RenderControl(w);
regex.RenderControl(w);
}
}
I checked few events or methods for this but they got fired after btnA_click event.
I am kind of newbie in this.
Any event or method i am missing? Any suggestion accepted.
Thanks in Advance...

You should try to set the default value on TextBox.LostFocus event. This event fires immediately after focus is lost from the control (TextBox).

Related

Dropdownlist changing the selected value when control is out of focus

I have several comboboxes with the same properties.
Dropdownstyle : Dropdownlist
AutoCompleteMode: SuggestAppend
AutoCompleteSource: ListItems
For example, I have a dropdownlist cboxStates that has 50 states of United States of America in Items Collection entered manually. When I type in WI, it is highlighted among WA,WV,WI,WY but if I tab over/press enter/mouse click on another control, WA is selected instead of WI which is highlighted. This is total random and it happens to comboboxes that are binded dynamically. And also, they do not have any events.
This seems to be an issue that has been submitted to Connect. There's a workaround there which extends the default ComboBox control and fixes the issue. The extended ComboBox code is horribly formatted on the Connect site, so here's the nicer version :)
public class BetterComboBox : ComboBox
{
private int _windows7CorrectedSelectedIndex = -1;
private int? _selectedIndexWhenDroppedDown = null;
protected override void OnDropDown(EventArgs e)
{
_selectedIndexWhenDroppedDown = SelectedIndex;
base.OnDropDown(e);
}
private bool _onDropDownClosedProcessing = false;
protected override void OnDropDownClosed(EventArgs e)
{
if (_selectedIndexWhenDroppedDown != null && _selectedIndexWhenDroppedDown != SelectedIndex)
{
try
{
_onDropDownClosedProcessing = true;
OnSelectionChangeCommitted(e);
}
finally
{
_onDropDownClosedProcessing = false;
}
}
base.OnDropDownClosed(e);
if (SelectedIndex != _windows7CorrectedSelectedIndex)
{
SelectedIndex = _windows7CorrectedSelectedIndex;
OnSelectionChangeCommitted(e);
}
}
protected override void OnSelectionChangeCommitted(EventArgs e)
{
if (!_onDropDownClosedProcessing)
_windows7CorrectedSelectedIndex = SelectedIndex;
_selectedIndexWhenDroppedDown = null;
base.OnSelectionChangeCommitted(e);
}
protected override void OnSelectedIndexChanged(EventArgs e)
{
bool alreadyMatched = true;
if (_windows7CorrectedSelectedIndex != SelectedIndex)
{
_windows7CorrectedSelectedIndex = SelectedIndex;
alreadyMatched = false;
}
base.OnSelectedIndexChanged(e);
//when not dropped down, the SelectionChangeCommitted event does not fire upon non-arrow keystrokes due (I suppose) to AutoComplete behavior
//this is not acceptable for my needs, and so I have come up with the best way to determine when to raise the event, without causing duplication of the event (alreadyMatched)
//and without causing the event to fire when programmatic changes cause SelectedIndexChanged to be raised (_processingKeyEventArgs implies user-caused)
if (!DroppedDown && !alreadyMatched && _processingKeyEventArgs)
OnSelectionChangeCommitted(e);
}
private bool _processingKeyEventArgs = false;
protected override bool ProcessKeyEventArgs(ref Message m)
{
try
{
_processingKeyEventArgs = true;
return base.ProcessKeyEventArgs(ref m);
}
finally
{
_processingKeyEventArgs = false;
}
}
}

Programically adding child controls to a asp.net composite control

Not found anything that directly answers my problem, so hopefully someone can shed some light on it.
I have two Composite Controls, lets call them BudgetTable and BudgetTableItem, where BudgetTable contains a list of BudgetTableItem.
So far everything works so long as I add new RowItems in the HTML View - when I add one programmatically it appears, but doesn't survive postback.
I can only assume I'm doing something boneheaded with ViewState, and would appreciate any pointers!
Thanks in advance.
The HTML:
<hea:BudgetTable runat="server" ID="btTest" MaximumFundingAvailable="7000" CssClass="bob">
<Items>
<hea:BudgetTableItem runat="server" Description="Test1" />
<hea:BudgetTableItem runat="server" Description="Test2" />
<hea:BudgetTableItem runat="server" Description="Test3" />
</Items>
</hea:BudgetTable>
The code behind:
[PersistenceMode(PersistenceMode.InnerProperty)]
[ParseChildren(true)]
public class BudgetTableItem : CompositeControl {
private TextBox _description = new TextBox();
private TextBox _cost = new TextBox();
private CheckBox _heaFunded = new CheckBox();
/*public delegate void AddRow();
public delegate void RemoveRow(BudgetTableItem item);
public event AddRow AddNewRow;
public event RemoveRow RemoveNewRow;*/
public string ItemName {
get {
var viewstate = ViewState["ItemName"];
return (viewstate is string) ? (string)viewstate : "default";
}
set {
ViewState["ItemName"] = value;
}
}
public bool ShowRemoveRow {
get {
var viewstate = ViewState["ShowRemoveRow"];
return (viewstate != null && viewstate is bool) ? (bool)viewstate : false;
}
set {
ViewState["ShowRemoveRow"] = value;
}
}
public bool ShowAddRow {
get {
var viewstate = ViewState["ShowAddRow"];
return (viewstate != null && viewstate is bool) ? (bool)viewstate : false;
}
set {
ViewState["ShowAddRow"] = value;
}
}
public string Description {
get {
return _description.Text;
}
set {
_description.Text = value;
}
}
public decimal Cost {
get {
decimal cost =0;
decimal.TryParse(_cost.Text, out cost);
return cost;
}
set {
_cost.Text = value.ToString();
}
}
public bool HeaFunded {
get {
return _heaFunded.Checked;
}
set {
_heaFunded.Checked = value;
}
}
protected override void CreateChildControls() {
Controls.Clear();
HtmlTableCell tableCell1 = new HtmlTableCell();
HtmlTableCell tableCell2 = new HtmlTableCell();
HtmlTableCell tableCell3 = new HtmlTableCell();
HtmlTableCell tableCell4 = new HtmlTableCell();
tableCell1.Attributes.Add("class", "col1");
tableCell2.Attributes.Add("class", "col2");
tableCell3.Attributes.Add("class", "col3");
tableCell4.Attributes.Add("class", "col4");
tableCell1.Controls.Add(_description);
tableCell2.Controls.Add(_cost);
tableCell3.Controls.Add(_heaFunded);
/*if (ShowAddRow || ShowRemoveRow) {
Button addNewButton = new Button();
addNewButton.Text = (ShowAddRow) ? "Add Row" : "Remove";
if (ShowAddRow) {
addNewButton.Click += new EventHandler(addNewButton_Click);
}
if (ShowRemoveRow) {
addNewButton.Click += new EventHandler(removeButton_Click);
}
tableCell4.Controls.Add(addNewButton);
}
else{*/
tableCell4.InnerHtml = " ";
//}
Controls.Add(tableCell1);
Controls.Add(tableCell2);
Controls.Add(tableCell3);
Controls.Add(tableCell4);
}
/*void addNewButton_Click(object sender, EventArgs e) {
if (AddNewRow != null) {
AddNewRow();
}
}*/
/*void removeButton_Click(object sender, EventArgs e) {
if (RemoveNewRow != null) {
RemoveNewRow(this);
}
}*/
protected override void RecreateChildControls() {
EnsureChildControls();
}
public override void RenderBeginTag(HtmlTextWriter writer) {
writer.Write("<tr>");
}
public override void RenderEndTag(HtmlTextWriter writer) {
writer.Write("</tr>");
}
}
Controls, custom or otherwise that require a ViewState and wish to receive events should be created in Init.
Http is stateless. Your entire page with all its controls is recreated on every postback. Controls that you add in the design view, are added to your designer.cs file, and created for you. When you add controls yourself, you must write code to recreate the controls on every PostBack that occurs later.
You can use the session to remember which controls were added by code and add them on later PostBacks.

How to correctly override the TextBox.Text property

In Windows Forms and C#, I am inheriting from the TextBox class. I override the Text property from TextBox. Everything goes well until I try to use the TextChanged event. The OnTextChanged event does not work properly here, as the Text.set property is not invoked.
Initial field content 123, txpText.Text = 123
Field content changed to a , txpText.Text still 123
Field content changed to aa , txpText.Text still 123
Field content changed to aaa , txpText.Text still 123
Here is my custom TextBox code
public class ShowPartialTextBox : System.Windows.Forms.TextBox
{
private string _realText;
public override string Text
{
get { return _realText; }
set // <--- Not invoked when TextChanged
{
if (value != _realText)
{
_realText = value;
base.Text = _maskPartial(_realText);
//I want to make this _maskPartial irrelevant
}
}
}
protected override void OnTextChanged(EventArgs e)
{
//Always called. Manually invoke Text.set here? How?
base.OnTextChanged(e);
}
private string _maskPartial(string txt)
{
if (txt == null)
return string.Empty;
if (_passwordChar == default(char))
return txt;
if (txt.Length <= _lengthShownLast)
return txt;
int idxlast = txt.Length - _lengthShownLast;
string result = _lpad(_passwordChar, idxlast) + txt.Substring(idxlast);
return result;
}
}
Here is the Form class
public partial class Form1 : Form
{
private ShowPartialTextBox txpText;
private void InitializeComponent()
{
txpText = new ShowPartialTextBox();
txpText.Text "123";
txpText.TextChanged += new System.EventHandler(this.txpText_TextChanged);
}
private void txpText_TextChanged(object sender, EventArgs e)
{
label1.Text = txpText.Text; //always shows 123
}
}
I use _maskPartial. It is altering the displayed Text, while still preserving its real content. I want this custom TextBox to "almost" simulate PasswordChar property, with showing the last x characters.
Easy to see when you set a breakpoint on the Text property setter. You assume that typing in the text box will call the setter. It doesn't. One fix is this:
protected override void OnTextChanged(EventArgs e) {
_realText = base.Text;
base.OnTextChanged(e);
}
But you'll have to make that work with _maskPartial(), it surely isn't irrelevant.

Can I hide Value in NumericUpDown control?

Lets say we have 0 displayed in value field of the control and I want that if the value is 0 - display string.Empty (I know that the type of value is decimal and there can be no string inserted instead of decimals in it, but still... Maybe there is some formatting possible there?).
Note: This is dependent on the current implementation of NumericUpDown.
What you need to do is create a new control that inherits from NumericUpDown such that:
public partial class SpecialNumericUpDown : NumericUpDown
{
public SpecialNumericUpDown()
{
InitializeComponent();
}
protected override void UpdateEditText()
{
if (this.Value != 0)
{
base.UpdateEditText();
}
else
{
base.Controls[1].Text = "";
}
}
}
public partial class MyNumericUpDown : NumericUpDown
{
public override string Text
{
get
{
if (base.Text.Length == 0)
{
return "0";
}
else
{
return base.Text;
}
}
set
{
if (value.Equals("0"))
{
base.Text = "";
}
else
{
base.Text = value;
}
}
}
}
It seems that there is only very limited support for changing the formatting.
I have not tried this myself. But you could create a subclass and override the UpdateEditText method to support your custom format. Something like this:
protected override void UpdateEditText()
{
this.Text = Value.ToString(); // Insert your formatting here
}
An easier solution is calling the ResetText() method. You can restore the text changing the Value property.
Example code to hide text when NumericUpDown control is disabled, and restore it on enabled
private void NumericUpDown_EnabledChanged(object sender, EventArgs e)
{
if (numericUpDown.Enabled)
{
if (numericUpDown.Tag != null)
{
// Restore last value
numericUpDown.Value = (decimal)numericUpDown.Tag;
}
}
else
{
// Save last value
numericUpDown.Tag = numericUpDown.Value;
// Just to force value change
numericUpDown.Value = (numericUpDown.Value > numericUpDown.Minimum ? numericUpDown.Minimum : numericUpDown.Maximum);
// Clear text
numericUpDown.ResetText();
}
}
If you only want to hide the value from the user, you can make ForeColor the same as BackColor so the value inside NumericUpDown will be invisible to the user.

C# validating data in multiple text boxes?

I have a C# form with multiple text boxes. Before proceeding I need to validate the inputs in the each text box. If my validation rule for each text box is same, Do I have any way to apply the same rule for all the fields at once. And my desired output is same. (I want to change the backcolour of the relevant textbox into pink) I mean I don't want to use anything like
validate_txtName();
validate_txtAddress();
validate_txtCity();
There should be some standard and easy way to do this.. I am seeking of that way ;)
First, put all the textboxes in a list. Then apply the ForEach function on the list, passing as argument the lambda expression that represents you're validation rule.
Edit:
I've found this example in my own code:
Core.Model.Settings.Labels.ToList()
.ForEach(x => schedulerStorage1.Appointments.Labels.Add(Color.FromArgb(x.ARGB), x.LabelName));
maybe foreach loop? :)
Write you own control which accepts a regular expression string for validation check during design time. At execution time handle the Validating event with one common handler. Following code does this. You can remove the errorprovider and just use the backcolor logic.
public class ValidatedTextBox : TextBox
{
private IContainer components;
private Color m_OldBackColor;
[Description("Color to be set when validation fails.")]
public Color BackColorOnFailedValidation
{
get
{
return m_BackColorOnFailedValidation;
}
set
{
m_BackColorOnFailedValidation = value;
}
}
private Color m_BackColorOnFailedValidation = Color.Yellow;
[Description("Message displayed by the error provider.")]
public string ErrorMessage
{
get
{
return m_ErrorMessage;
}
set
{
m_ErrorMessage = value;
}
}
private string m_ErrorMessage = "";
[Description("Regular expression string to validate the text.")]
public string RegularExpressionString
{
get
{
return m_RegularExpressionString;
}
set
{
m_RegularExpressionString = value;
}
}
private string m_RegularExpressionString = "";
private ErrorProvider errorProvider1;
[Browsable(false)]
public bool Valid
{
get
{
return m_Valid;
}
}
private bool m_Valid = true;
public ValidatedTextBox()
: base()
{
InitializeComponent();
m_OldBackColor = this.BackColor;
this.Validating += new System.ComponentModel.CancelEventHandler(ValidatedTextBox_Validating);
errorProvider1.Clear();
}
void ValidatedTextBox_Validating(object sender, System.ComponentModel.CancelEventArgs e)
{
if (RegularExpressionString != string.Empty)
{
Regex regex = new Regex(RegularExpressionString);
m_Valid = regex.IsMatch(Text);
SetBackColor();
if (!Valid)
{
errorProvider1.SetError(this, this.ErrorMessage);
this.Focus();
}
else
{
errorProvider1.Clear();
}
}
}
private void SetBackColor()
{
if (!Valid)
BackColor = BackColorOnFailedValidation;
else
BackColor = m_OldBackColor;
}
private void InitializeComponent()
{
this.components = new System.ComponentModel.Container();
this.errorProvider1 = new System.Windows.Forms.ErrorProvider(this.components);
((System.ComponentModel.ISupportInitialize)(this.errorProvider1)).BeginInit();
this.SuspendLayout();
((System.ComponentModel.ISupportInitialize)(this.errorProvider1)).EndInit();
this.ResumeLayout(false);
}
}
you can try this i suppose.. Put all the controls you want to validate in a grouper control and call validate on all the controls inside the grouper using a foreach loop

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