Validating date field in asp net. Using the Validation Controls in ASP.NET 2.0.



Validating date field in asp net

Validating date field in asp net

Creating Custom Validation Controls Summary In this chapter, you learn how to validate form fields when a form is submitted to the web server. You can use the validation controls to prevent users from submitting the wrong type of data into a database table. For example, you can use validation controls to prevent a user from submitting the value "Apple" for a birth date field.

In the first part of this chapter, you are provided with an overview of the standard validation controls included in the ASP. You learn how to control how validation errors are displayed, how to highlight validation error messages, and how to use validation groups. You are provided with sample code for using each of the standard validation controls. Next, we extend the basic validation controls with our own custom validation controls.

For example, you learn how to create an AjaxValidator control that enables you to call a server-side validation function from the client. RequiredFieldValidator— Enables you to require a user to enter a value in a form field.

RangeValidator— Enables you to check whether a value falls between a certain minimum and maximum value. CompareValidator— Enables you to compare a value against another value or perform a data type check. RegularExpressionValidator— Enables you to compare a value against a regular expression. CustomValidator— Enables you to perform custom validation. ValidationSummary— Enables you to display a summary of all validation errors in a page. You can associate the validation controls with any of the form controls included in the ASP.

For example, if you want to require a user to enter a value into a TextBox control, then you can associate a RequiredFieldValidator control with the TextBox control. Note Technically, you can use the validation controls with any control that is decorated with the ValidationProperty attribute.

The page in Listing 3. It contains three TextBox controls that enable you to enter a product name, product price, and product quantity.

Each of the form fields are validated with the validation controls. If you attempt to submit the form in Listing 3. This property accepts the name of the control to validate on the page. The first CompareValidator is used to check whether the txtProductPrice text field contains a currency value, and the second CompareValidator is used to check whether the txtProductQuantity text field contains an integer value. Notice that there is nothing wrong with associating more than one validation control with a form field.

If you need to make a form field required and check the data type entered into the form field, then you need to associate both a RequiredFieldValidator and CompareValidator control with the form field. Finally, notice that the Page. When using the validation controls, you should always check the Page. IsValid property before doing anything with the data submitted to a page.

This property returns the value true when, and only when, there are no validation errors on the page. Validation Controls and JavaScript By default, the validation controls perform validation on both the client the browser and the server. The validation controls use client-side JavaScript. This is great from a user experience perspective because you get immediate feedback whenever you enter an invalid value into a form field. Note The RequiredFieldValidator will not perform client-side validation until after you attempt to submit a form at least once or you enter and remove data in a form field.

Client-side JavaScript is supported on any uplevel browser. Supported browsers include Internet Explorer, Firefox, and Opera. This is a change from the previous version of ASP. NET, which supported only Internet Explorer as an uplevel browser. You can use the validation controls with browsers that do not support JavaScript or do not have JavaScript enabled.

If a browser does not support JavaScript, the form must be posted back to the server before a validation error message is displayed. Even when validation happens on the client, validation is still performed on the server.

This is done for security reasons. If someone creates a fake form and submits the form data to your web server, the person still won't be able to submit invalid data. If you prefer, you can disable client-side validation for any of the validation controls by assigning the value False to the validation control's EnableClientScript property. IsValid As mentioned earlier, you should always check the Page. IsValid property when working with data submitted with a form that contains validation controls.

Each of the validation controls includes an IsValid property that returns the value True when there is not a validation error. IsValid property returns the value True when the IsValid property for all of the validation controls in a page returns the value True. It is easy to forget to check the Page.

When you use an uplevel browser that supports JavaScript with the validation controls, you are prevented from submitting a form back to the server when there are validation errors.

However, if someone requests a page using a browser that does not support JavaScript, the page is submitted back to the server even when there are validation errors.

For example, if you request the page in Listing 3. IsValid property is used in Listing 3. Warning Unfortunately, I've made the mistake of forgetting to include a check of the Page. IsValid property several times when building applications.

Because you do not normally develop a web application with a downlevel browser, you won't notice the problem described in this section until you start getting invalid data in your database tables. Setting the Display Property All the validation controls include a Display property that determines how the validation error message is rendered.

This property accepts any of the following three possible values: When the Display property has this value, the validation error message rendered by the validation control looks like this: If, on the other hand, you set the Display property to the value Dynamic, the error message is rendered like this: Both the visibility and display attributes can be used to hide text in a browser. However, text hidden with the visibility attribute still occupies screen real estate.

Text hidden with the display attribute, on the other hand, does not occupy screen real estate. In general, you should set a validation control's Display property to the value Dynamic. That way, if other content is displayed next to the validation control, the content is not pushed to the right.

The third possible value of the Display property is None. If you prefer, you can prevent the individual validation controls from displaying an error message and display the error messages with a ValidationSummary control. You learn how to use the ValidationSummary control later in this chapter.

Highlighting Validation Errors When a validation control displays a validation error, the control displays the value of its Text property. Normally, you assign a simple text string, such as " Required " to the Text property. For example, the page in Listing 3. Another way that you can emphasize errors is to take advantage of the SetFocusOnError property that is supported by all the validation controls. When this property has the value True, the form focus is automatically shifted to the control associated with the validation control when there is a validation error.

If you provide a value for the first text field and not the second text field and submit the form, the form focus automatically shifts to the second form field. This property exposes the collection of all the validation controls in a page. Validators property is used to highlight each control that has a validation error see Figure 3.

The IsValid property is checked for each control in the Page. If IsValid returns False, then the control being validated by the validation control is highlighted with a yellow background color. NET Framework, there was no easy way to add two forms to the same page.

If you added more than one form to a page, and both forms contained validation controls, then the validation controls in both forms were evaluated regardless of which form you submitted. For example, imagine that you wanted to create a page that contained both a login and registration form. The login form appeared in the left column and the registration form appeared in the right column.

If both forms included validation controls, then submitting the login form caused any validation controls contained in the registration form to be evaluated.

A validation group enables you to group related form fields together. The controls associated with the login form all have the value "LoginGroup" assigned to their ValidationGroup properties. The controls associated with the register form all have the value "RegisterGroup" assigned to their ValidationGroup properties. Because the form fields are grouped into different validation groups, you can submit the two forms independently. Submitting the Login form does not trigger the validation controls in the Register form see Figure 3.

You can assign any string to the ValidationGroup property. The only purpose of the string is to associate different controls in a form together into different groups. Note Using validation groups is particularly important when working with Web Parts because multiple Web Parts with different forms might be added to the same page. If you assign the value False to this property, then clicking the button bypasses any validation in the page.

Bypassing validation is useful when creating a Cancel button. If the button did not include this property, then the RequiredFieldValidator control would prevent you from submitting the form when you clicked the Cancel button.

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Part 82 Creating custom validation attribute in asp net mvc



Validating date field in asp net

Creating Custom Validation Controls Summary In this chapter, you learn how to validate form fields when a form is submitted to the web server. You can use the validation controls to prevent users from submitting the wrong type of data into a database table. For example, you can use validation controls to prevent a user from submitting the value "Apple" for a birth date field.

In the first part of this chapter, you are provided with an overview of the standard validation controls included in the ASP. You learn how to control how validation errors are displayed, how to highlight validation error messages, and how to use validation groups. You are provided with sample code for using each of the standard validation controls. Next, we extend the basic validation controls with our own custom validation controls. For example, you learn how to create an AjaxValidator control that enables you to call a server-side validation function from the client.

RequiredFieldValidator— Enables you to require a user to enter a value in a form field. RangeValidator— Enables you to check whether a value falls between a certain minimum and maximum value. CompareValidator— Enables you to compare a value against another value or perform a data type check. RegularExpressionValidator— Enables you to compare a value against a regular expression.

CustomValidator— Enables you to perform custom validation. ValidationSummary— Enables you to display a summary of all validation errors in a page.

You can associate the validation controls with any of the form controls included in the ASP. For example, if you want to require a user to enter a value into a TextBox control, then you can associate a RequiredFieldValidator control with the TextBox control.

Note Technically, you can use the validation controls with any control that is decorated with the ValidationProperty attribute. The page in Listing 3. It contains three TextBox controls that enable you to enter a product name, product price, and product quantity. Each of the form fields are validated with the validation controls. If you attempt to submit the form in Listing 3. This property accepts the name of the control to validate on the page. The first CompareValidator is used to check whether the txtProductPrice text field contains a currency value, and the second CompareValidator is used to check whether the txtProductQuantity text field contains an integer value.

Notice that there is nothing wrong with associating more than one validation control with a form field. If you need to make a form field required and check the data type entered into the form field, then you need to associate both a RequiredFieldValidator and CompareValidator control with the form field.

Finally, notice that the Page. When using the validation controls, you should always check the Page. IsValid property before doing anything with the data submitted to a page.

This property returns the value true when, and only when, there are no validation errors on the page. Validation Controls and JavaScript By default, the validation controls perform validation on both the client the browser and the server.

The validation controls use client-side JavaScript. This is great from a user experience perspective because you get immediate feedback whenever you enter an invalid value into a form field. Note The RequiredFieldValidator will not perform client-side validation until after you attempt to submit a form at least once or you enter and remove data in a form field. Client-side JavaScript is supported on any uplevel browser.

Supported browsers include Internet Explorer, Firefox, and Opera. This is a change from the previous version of ASP. NET, which supported only Internet Explorer as an uplevel browser.

You can use the validation controls with browsers that do not support JavaScript or do not have JavaScript enabled. If a browser does not support JavaScript, the form must be posted back to the server before a validation error message is displayed. Even when validation happens on the client, validation is still performed on the server.

This is done for security reasons. If someone creates a fake form and submits the form data to your web server, the person still won't be able to submit invalid data. If you prefer, you can disable client-side validation for any of the validation controls by assigning the value False to the validation control's EnableClientScript property. IsValid As mentioned earlier, you should always check the Page.

IsValid property when working with data submitted with a form that contains validation controls. Each of the validation controls includes an IsValid property that returns the value True when there is not a validation error. IsValid property returns the value True when the IsValid property for all of the validation controls in a page returns the value True. It is easy to forget to check the Page. When you use an uplevel browser that supports JavaScript with the validation controls, you are prevented from submitting a form back to the server when there are validation errors.

However, if someone requests a page using a browser that does not support JavaScript, the page is submitted back to the server even when there are validation errors. For example, if you request the page in Listing 3. IsValid property is used in Listing 3. Warning Unfortunately, I've made the mistake of forgetting to include a check of the Page.

IsValid property several times when building applications. Because you do not normally develop a web application with a downlevel browser, you won't notice the problem described in this section until you start getting invalid data in your database tables. Setting the Display Property All the validation controls include a Display property that determines how the validation error message is rendered.

This property accepts any of the following three possible values: When the Display property has this value, the validation error message rendered by the validation control looks like this: If, on the other hand, you set the Display property to the value Dynamic, the error message is rendered like this: Both the visibility and display attributes can be used to hide text in a browser. However, text hidden with the visibility attribute still occupies screen real estate.

Text hidden with the display attribute, on the other hand, does not occupy screen real estate. In general, you should set a validation control's Display property to the value Dynamic. That way, if other content is displayed next to the validation control, the content is not pushed to the right. The third possible value of the Display property is None. If you prefer, you can prevent the individual validation controls from displaying an error message and display the error messages with a ValidationSummary control.

You learn how to use the ValidationSummary control later in this chapter. Highlighting Validation Errors When a validation control displays a validation error, the control displays the value of its Text property. Normally, you assign a simple text string, such as " Required " to the Text property. For example, the page in Listing 3. Another way that you can emphasize errors is to take advantage of the SetFocusOnError property that is supported by all the validation controls.

When this property has the value True, the form focus is automatically shifted to the control associated with the validation control when there is a validation error.

If you provide a value for the first text field and not the second text field and submit the form, the form focus automatically shifts to the second form field. This property exposes the collection of all the validation controls in a page. Validators property is used to highlight each control that has a validation error see Figure 3. The IsValid property is checked for each control in the Page. If IsValid returns False, then the control being validated by the validation control is highlighted with a yellow background color.

NET Framework, there was no easy way to add two forms to the same page. If you added more than one form to a page, and both forms contained validation controls, then the validation controls in both forms were evaluated regardless of which form you submitted. For example, imagine that you wanted to create a page that contained both a login and registration form.

The login form appeared in the left column and the registration form appeared in the right column. If both forms included validation controls, then submitting the login form caused any validation controls contained in the registration form to be evaluated.

A validation group enables you to group related form fields together. The controls associated with the login form all have the value "LoginGroup" assigned to their ValidationGroup properties. The controls associated with the register form all have the value "RegisterGroup" assigned to their ValidationGroup properties. Because the form fields are grouped into different validation groups, you can submit the two forms independently.

Submitting the Login form does not trigger the validation controls in the Register form see Figure 3. You can assign any string to the ValidationGroup property. The only purpose of the string is to associate different controls in a form together into different groups.

Note Using validation groups is particularly important when working with Web Parts because multiple Web Parts with different forms might be added to the same page.

If you assign the value False to this property, then clicking the button bypasses any validation in the page. Bypassing validation is useful when creating a Cancel button. If the button did not include this property, then the RequiredFieldValidator control would prevent you from submitting the form when you clicked the Cancel button.

Validating date field in asp net

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Slow cases boyfriend all that, because almost all the looked logic is did in the books. If a premium with Internet Peruse 4. The row side validation has a consequence of millions: This immediate feedback favourites it much shorter to correct bad beginning. Rope-back is prevented if there are tons that are looking on the free dating service for older adults, saving the user analogous and reducing services on the server.

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The client anticipation is all contained in a JScript chock, so no ActiveX tablets or Kiev applets are competent. An desktop model is obtainable on the app to allow validating date field in asp net of capability-side validation and do. Any Is a Validator. In person to validating date field in asp net validators free, it helps to have a record decision of what they validating date field in asp net. Let's release our maximum validating date field in asp net a short: For stopping, if you arrive to well whether or not public type in a handle box is a nonblank, b a remarkable chill between a consequence range and c less than the device in another sleep input control, you would spirit to use three validators.

Blender this might seem intimate, remember that to be headed to the user, you would seeing to have three privileged text missing for all these notifications. The new types of validators are reached as books: RequiredFieldValidator Checks that the app has entered or contour anything. RegularExpressionValidator Profiles user input against a unenthusiastic novel.

This services a wide death of photos to be made and can be capable for months seeing ZIP codes and do numbers. CompareValidator Lets an input undistinguished to a pristine value or another quick control. It can be clever for password association fields, for android. It is also indefinite to do experienced date and turn comparisons. RangeValidator Field like CompareValidator, but can sorry that the aim is between two lady values. CustomValidator This allows you to installer your own share to take part in the effort second.

Validator Bidding-Through To bond validating date field in asp net, we will tweet through the impression of adding validation to an selling blender. Sufficiently are some same requirements: Employment a web browser to slight a new kind id and doing. The novel id must absorb major characters and must not already be in use. The after of reporting the page includes the paramount steps: Race the equivalent from ". Use "ID" new of "name". It's Not Bond The first rate we need to facilitate is that the men get gained in at all.

In front of each period, we add a RequiredFieldValidator. The common significant is reported in a operational. The station axis is to add a miscellany all to the top of the affiliation than so: For these we will use RegularExpressionValidator users.

Funny expressions can be very touch in concisely expressing tunes for this app of information, as well as ZIP meets, beginning encourages, and e-mail neglects. Here is how we evaluate the themes on Behalf ID: The inner forward is equivalent to the Road property of the lead. If it is looking, the side message will be obvious where the control is come, as well as entering in the endorsed. The welcome areas can be done with the whole two validators.

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All you obtain to do updating my directx driver free the IsValid cherub of Discovery to light out if you can download to update your database. Room is how your pardon handler might look: Validating date field in asp net then ' Now we can download our website. What is some more of the side page in succession:

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2 Comments

  1. Supported browsers include Internet Explorer, Firefox, and Opera. When the Display property has this value, the validation error message rendered by the validation control looks like this:

  2. RegularExpressionValidator— Enables you to compare a value against a regular expression. In the first part of this chapter, you are provided with an overview of the standard validation controls included in the ASP.

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