Let’s understand how this tag works with working examples.<\/p>\n\n\n\n
What is the <apex:param> Tag?<\/strong><\/h2>\n\n\n\nThe <apex:param> acts as a messenger between your Visualforce page and your Apex controller. It becomes useful when you want to:<\/p>\n\n\n\n
\n- pass row-specific data from a table<\/li>\n\n\n\n
- Send dynamic values through buttons or links<\/li>\n\n\n\n
- call Apex from JavaScript<\/li>\n\n\n\n
- trigger partial page updates with parameters<\/li>\n<\/ul>\n\n\n\n
Parents Component of apex:param <\/strong><\/h2>\n\n\n\nThe apex:param tag can’t work on its own, and it always needs a parent that actually triggers the action. The tags that support apex:param as a child element are:<\/p>\n\n\n\n
\n- <apex:actionFunction><\/li>\n\n\n\n
- <apex:actionSupport><\/li>\n\n\n\n
- <apex:commandLink><\/li>\n\n\n\n
- <apex:outputLink><\/li>\n\n\n\n
- <apex:outputText><\/li>\n\n\n\n
- <flow:interview><\/li>\n<\/ul>\n\n\n\n
For apex:param, the value attribute must always be specified, and with it, either the assignedto or name attribute is also required.<\/p>\n\n\n\n
What are the meanings of these attributes, and how are they used? I am going to explain in the next part with an example.<\/p>\n\n\n\n
Apex Class<\/h2>\n\n\n\npublic class paramtest {\n public string value { get; set;}\n \n public void testdirect(){\n system.debug(value);\n }\n public void testinput(){\n value = apexpages.currentPage().getParameters().get('inpval');\n system.debug(value);\n }\n}<\/pre>\n\n\n\nThis apex class does not have much use, and the only important piece of code in it is the first line of the function testinput(). <\/p>\n\n\n\n
The getParameters() gets all the parameters and makes a map out of them, with the key being the name of the parameter. This name is the same name used in the apex:param attribute.<\/p>\n\n\n\n
How apex:param Works in Visualforce?<\/h2>\n\n\n\n<apex:page controller="paramtest" docType="html-5.0">\n<apex:form>\n\n<apex:commandbutton action="{!testdirect}" reRender="test" value="Static value">\n<apex:param assignTo="{!value}" value="The static value that was set from vf page"\/>\n<\/apex:commandbutton><br\/>\n<input type="text" id="testinput"\/>\n<input type="button" onclick="testinputJS()" value="Dynamic Value" class="btn"\/>\n<apex:outputPanel id="test">\n<apex:outputText value="{!value}"\/>\n<\/apex:outputPanel>\n<apex:actionFunction action="{!testinput}" name="passToController" rerender="test">\n<apex:param value="" name="inpval"\/>\n<\/apex:actionFunction>\n<\/apex:form>\n<script>\nfunction testinputJS(){\nvar str = document.getElementById('testinput').value;\nif(str.length >4){\nstr= str.substring(0,4);\n}\npassToController(str);\n}\n<\/script>\n<\/apex:page><\/pre>\n\n\n\nIn the VF page, we have used <apex:param> at two places, one in the commandbutton and the other in the ActionFunction<\/a>. <\/p>\n\n\n\nThe <apex:param>, which is in the command button, has a value specified to it and is also assigned to a variable in the controller. <\/p>\n\n\n\n
This value will be passed to the variable in the controller if the button is clicked. This type of parameter passing is helpful when you are using it in a table over iterated values.<\/p>\n\n\n\n
The other is with ActionFunction, where the name of the value is specified; however, if the value is not specified, and left blank. <\/p>\n\n\n\n
Here we will have to manually get the data and store it in a variable, like I had done earlier in the VF page.<\/p>\n\n\n\n
Output<\/h2>\n\n\n\n
The output of both actions will be like:<\/p>\n\n\n\n![\"apex:param\"](\"https:\/\/cdnblog.webkul.com\/blog\/wp-content\/uploads\/2017\/08\/gwinamvbyacyp66.jpg\")
<\/a><\/figure>\n\n\n\n![\"apex:param\"](\"https:\/\/cdnblog.webkul.com\/blog\/wp-content\/uploads\/2017\/08\/g708f0issohqto6.jpg\")
<\/a><\/figure>\n\n\n\nThat\u2019s all about using the apex:param tag. It won’t revolutionize your development process, but it really solves the passing of values from Visualforce to Apex without any hassle.<\/p>\n\n\n\n
Support<\/h2>\n\n\n\n
Our team can audit, optimize, and redesign your Salesforce setup for reliability and speed. Reach out at support@webkul.com<\/strong><\/a>.<\/p>\n\n\n\nNeed dedicated expertise? Hire Webkul Salesforce developers <\/a>to stabilize and future-proof your org.<\/p>\n\n\n\n<\/p>\n","protected":false},"excerpt":{"rendered":"
Parents Component of apex:param <\/strong><\/h2>\n\n\n\nThe apex:param tag can’t work on its own, and it always needs a parent that actually triggers the action. The tags that support apex:param as a child element are:<\/p>\n\n\n\n
\n- <apex:actionFunction><\/li>\n\n\n\n
- <apex:actionSupport><\/li>\n\n\n\n
- <apex:commandLink><\/li>\n\n\n\n
- <apex:outputLink><\/li>\n\n\n\n
- <apex:outputText><\/li>\n\n\n\n
- <flow:interview><\/li>\n<\/ul>\n\n\n\n
For apex:param, the value attribute must always be specified, and with it, either the assignedto or name attribute is also required.<\/p>\n\n\n\n
What are the meanings of these attributes, and how are they used? I am going to explain in the next part with an example.<\/p>\n\n\n\n
Apex Class<\/h2>\n\n\n\npublic class paramtest {\n public string value { get; set;}\n \n public void testdirect(){\n system.debug(value);\n }\n public void testinput(){\n value = apexpages.currentPage().getParameters().get('inpval');\n system.debug(value);\n }\n}<\/pre>\n\n\n\nThis apex class does not have much use, and the only important piece of code in it is the first line of the function testinput(). <\/p>\n\n\n\n
The getParameters() gets all the parameters and makes a map out of them, with the key being the name of the parameter. This name is the same name used in the apex:param attribute.<\/p>\n\n\n\n
How apex:param Works in Visualforce?<\/h2>\n\n\n\n<apex:page controller="paramtest" docType="html-5.0">\n<apex:form>\n\n<apex:commandbutton action="{!testdirect}" reRender="test" value="Static value">\n<apex:param assignTo="{!value}" value="The static value that was set from vf page"\/>\n<\/apex:commandbutton><br\/>\n<input type="text" id="testinput"\/>\n<input type="button" onclick="testinputJS()" value="Dynamic Value" class="btn"\/>\n<apex:outputPanel id="test">\n<apex:outputText value="{!value}"\/>\n<\/apex:outputPanel>\n<apex:actionFunction action="{!testinput}" name="passToController" rerender="test">\n<apex:param value="" name="inpval"\/>\n<\/apex:actionFunction>\n<\/apex:form>\n<script>\nfunction testinputJS(){\nvar str = document.getElementById('testinput').value;\nif(str.length >4){\nstr= str.substring(0,4);\n}\npassToController(str);\n}\n<\/script>\n<\/apex:page><\/pre>\n\n\n\nIn the VF page, we have used <apex:param> at two places, one in the commandbutton and the other in the ActionFunction<\/a>. <\/p>\n\n\n\nThe <apex:param>, which is in the command button, has a value specified to it and is also assigned to a variable in the controller. <\/p>\n\n\n\n
This value will be passed to the variable in the controller if the button is clicked. This type of parameter passing is helpful when you are using it in a table over iterated values.<\/p>\n\n\n\n
The other is with ActionFunction, where the name of the value is specified; however, if the value is not specified, and left blank. <\/p>\n\n\n\n
Here we will have to manually get the data and store it in a variable, like I had done earlier in the VF page.<\/p>\n\n\n\n
Output<\/h2>\n\n\n\n
The output of both actions will be like:<\/p>\n\n\n\n<\/a><\/figure>\n\n\n\n<\/a><\/figure>\n\n\n\nThat\u2019s all about using the apex:param tag. It won’t revolutionize your development process, but it really solves the passing of values from Visualforce to Apex without any hassle.<\/p>\n\n\n\n
Support<\/h2>\n\n\n\n
Our team can audit, optimize, and redesign your Salesforce setup for reliability and speed. Reach out at support@webkul.com<\/strong><\/a>.<\/p>\n\n\n\nNeed dedicated expertise? Hire Webkul Salesforce developers <\/a>to stabilize and future-proof your org.<\/p>\n\n\n\n<\/p>\n","protected":false},"excerpt":{"rendered":"
For apex:param, the value attribute must always be specified, and with it, either the assignedto or name attribute is also required.<\/p>\n\n\n\n
What are the meanings of these attributes, and how are they used? I am going to explain in the next part with an example.<\/p>\n\n\n\n
Apex Class<\/h2>\n\n\n\npublic class paramtest {\n public string value { get; set;}\n \n public void testdirect(){\n system.debug(value);\n }\n public void testinput(){\n value = apexpages.currentPage().getParameters().get('inpval');\n system.debug(value);\n }\n}<\/pre>\n\n\n\nThis apex class does not have much use, and the only important piece of code in it is the first line of the function testinput(). <\/p>\n\n\n\n
The getParameters() gets all the parameters and makes a map out of them, with the key being the name of the parameter. This name is the same name used in the apex:param attribute.<\/p>\n\n\n\n
How apex:param Works in Visualforce?<\/h2>\n\n\n\n<apex:page controller="paramtest" docType="html-5.0">\n<apex:form>\n\n<apex:commandbutton action="{!testdirect}" reRender="test" value="Static value">\n<apex:param assignTo="{!value}" value="The static value that was set from vf page"\/>\n<\/apex:commandbutton><br\/>\n<input type="text" id="testinput"\/>\n<input type="button" onclick="testinputJS()" value="Dynamic Value" class="btn"\/>\n<apex:outputPanel id="test">\n<apex:outputText value="{!value}"\/>\n<\/apex:outputPanel>\n<apex:actionFunction action="{!testinput}" name="passToController" rerender="test">\n<apex:param value="" name="inpval"\/>\n<\/apex:actionFunction>\n<\/apex:form>\n<script>\nfunction testinputJS(){\nvar str = document.getElementById('testinput').value;\nif(str.length >4){\nstr= str.substring(0,4);\n}\npassToController(str);\n}\n<\/script>\n<\/apex:page><\/pre>\n\n\n\nIn the VF page, we have used <apex:param> at two places, one in the commandbutton and the other in the ActionFunction<\/a>. <\/p>\n\n\n\nThe <apex:param>, which is in the command button, has a value specified to it and is also assigned to a variable in the controller. <\/p>\n\n\n\n
This value will be passed to the variable in the controller if the button is clicked. This type of parameter passing is helpful when you are using it in a table over iterated values.<\/p>\n\n\n\n
The other is with ActionFunction, where the name of the value is specified; however, if the value is not specified, and left blank. <\/p>\n\n\n\n
Here we will have to manually get the data and store it in a variable, like I had done earlier in the VF page.<\/p>\n\n\n\n
Output<\/h2>\n\n\n\n
The output of both actions will be like:<\/p>\n\n\n\n<\/a><\/figure>\n\n\n\n<\/a><\/figure>\n\n\n\nThat\u2019s all about using the apex:param tag. It won’t revolutionize your development process, but it really solves the passing of values from Visualforce to Apex without any hassle.<\/p>\n\n\n\n
Support<\/h2>\n\n\n\n
Our team can audit, optimize, and redesign your Salesforce setup for reliability and speed. Reach out at support@webkul.com<\/strong><\/a>.<\/p>\n\n\n\nNeed dedicated expertise? Hire Webkul Salesforce developers <\/a>to stabilize and future-proof your org.<\/p>\n\n\n\n<\/p>\n","protected":false},"excerpt":{"rendered":"
This apex class does not have much use, and the only important piece of code in it is the first line of the function testinput(). <\/p>\n\n\n\n
The getParameters() gets all the parameters and makes a map out of them, with the key being the name of the parameter. This name is the same name used in the apex:param attribute.<\/p>\n\n\n\n
How apex:param Works in Visualforce?<\/h2>\n\n\n\n<apex:page controller="paramtest" docType="html-5.0">\n<apex:form>\n\n<apex:commandbutton action="{!testdirect}" reRender="test" value="Static value">\n<apex:param assignTo="{!value}" value="The static value that was set from vf page"\/>\n<\/apex:commandbutton><br\/>\n<input type="text" id="testinput"\/>\n<input type="button" onclick="testinputJS()" value="Dynamic Value" class="btn"\/>\n<apex:outputPanel id="test">\n<apex:outputText value="{!value}"\/>\n<\/apex:outputPanel>\n<apex:actionFunction action="{!testinput}" name="passToController" rerender="test">\n<apex:param value="" name="inpval"\/>\n<\/apex:actionFunction>\n<\/apex:form>\n<script>\nfunction testinputJS(){\nvar str = document.getElementById('testinput').value;\nif(str.length >4){\nstr= str.substring(0,4);\n}\npassToController(str);\n}\n<\/script>\n<\/apex:page><\/pre>\n\n\n\nIn the VF page, we have used <apex:param> at two places, one in the commandbutton and the other in the ActionFunction<\/a>. <\/p>\n\n\n\nThe <apex:param>, which is in the command button, has a value specified to it and is also assigned to a variable in the controller. <\/p>\n\n\n\n
This value will be passed to the variable in the controller if the button is clicked. This type of parameter passing is helpful when you are using it in a table over iterated values.<\/p>\n\n\n\n
The other is with ActionFunction, where the name of the value is specified; however, if the value is not specified, and left blank. <\/p>\n\n\n\n
Here we will have to manually get the data and store it in a variable, like I had done earlier in the VF page.<\/p>\n\n\n\n
Output<\/h2>\n\n\n\n
The output of both actions will be like:<\/p>\n\n\n\n<\/a><\/figure>\n\n\n\n<\/a><\/figure>\n\n\n\nThat\u2019s all about using the apex:param tag. It won’t revolutionize your development process, but it really solves the passing of values from Visualforce to Apex without any hassle.<\/p>\n\n\n\n
Support<\/h2>\n\n\n\n
Our team can audit, optimize, and redesign your Salesforce setup for reliability and speed. Reach out at support@webkul.com<\/strong><\/a>.<\/p>\n\n\n\nNeed dedicated expertise? Hire Webkul Salesforce developers <\/a>to stabilize and future-proof your org.<\/p>\n\n\n\n<\/p>\n","protected":false},"excerpt":{"rendered":"
In the VF page, we have used <apex:param> at two places, one in the commandbutton and the other in the ActionFunction<\/a>. <\/p>\n\n\n\n The <apex:param>, which is in the command button, has a value specified to it and is also assigned to a variable in the controller. <\/p>\n\n\n\n This value will be passed to the variable in the controller if the button is clicked. This type of parameter passing is helpful when you are using it in a table over iterated values.<\/p>\n\n\n\n The other is with ActionFunction, where the name of the value is specified; however, if the value is not specified, and left blank. <\/p>\n\n\n\n Here we will have to manually get the data and store it in a variable, like I had done earlier in the VF page.<\/p>\n\n\n\n The output of both actions will be like:<\/p>\n\n\n\n That\u2019s all about using the apex:param tag. It won’t revolutionize your development process, but it really solves the passing of values from Visualforce to Apex without any hassle.<\/p>\n\n\n\n Our team can audit, optimize, and redesign your Salesforce setup for reliability and speed. Reach out at support@webkul.com<\/strong><\/a>.<\/p>\n\n\n\n Need dedicated expertise? Hire Webkul Salesforce developers <\/a>to stabilize and future-proof your org.<\/p>\n\n\n\n <\/p>\n","protected":false},"excerpt":{"rendered":"Output<\/h2>\n\n\n\n
<\/a><\/figure>\n\n\n\n<\/a><\/figure>\n\n\n\nSupport<\/h2>\n\n\n\n