# Set Flow Variable Values from a Visualforce Page

After you embed your flow in a Visualforce page, set the initial values of variables, record variables, collection variables, and record collection variables through the `<apex:param>` component.

:::note
You can set variables only at the beginning of an interview. The `<apex:param>` tags are evaluated only once, when the flow is launched.

You can set only variables that allow input access. If you reference a variable that doesn’t allow input access, attempts to set the variable are ignored. Compilation can fail for the Visualforce page, its `<apex:page>` component, or the Apex class.
:::

The following table lists the ways you can set a flow’s variable, record variable, and record collection variable values using Visualforce.

| Method                          | Variables                                                                                                                            | Record Variables                                                                                                                     | Collection Variables                                                                                                                 | Record Collection Variables                                                                                                          |
| ------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------ |
| Without a controller            | ![checkmark](https://a.sfdcstatic.com/developer-website/sfdocs/platform/media/salesforce-pages-developers-guide/checkmark_16x16.png) |                                                                                                                                      |                                                                                                                                      |                                                                                                                                      |
| With a standard controller      | ![checkmark](https://a.sfdcstatic.com/developer-website/sfdocs/platform/media/salesforce-pages-developers-guide/checkmark_16x16.png) | ![checkmark](https://a.sfdcstatic.com/developer-website/sfdocs/platform/media/salesforce-pages-developers-guide/checkmark_16x16.png) |                                                                                                                                      |                                                                                                                                      |
| With a standard List controller |                                                                                                                                      |                                                                                                                                      |                                                                                                                                      | ![checkmark](https://a.sfdcstatic.com/developer-website/sfdocs/platform/media/salesforce-pages-developers-guide/checkmark_16x16.png) |
| With a custom Apex controller   | ![checkmark](https://a.sfdcstatic.com/developer-website/sfdocs/platform/media/salesforce-pages-developers-guide/checkmark_16x16.png) | ![checkmark](https://a.sfdcstatic.com/developer-website/sfdocs/platform/media/salesforce-pages-developers-guide/checkmark_16x16.png) | ![checkmark](https://a.sfdcstatic.com/developer-website/sfdocs/platform/media/salesforce-pages-developers-guide/checkmark_16x16.png) | ![checkmark](https://a.sfdcstatic.com/developer-website/sfdocs/platform/media/salesforce-pages-developers-guide/checkmark_16x16.png) |
| With an Interview Map           | ![checkmark](https://a.sfdcstatic.com/developer-website/sfdocs/platform/media/salesforce-pages-developers-guide/checkmark_16x16.png) | ![checkmark](https://a.sfdcstatic.com/developer-website/sfdocs/platform/media/salesforce-pages-developers-guide/checkmark_16x16.png) | ![checkmark](https://a.sfdcstatic.com/developer-website/sfdocs/platform/media/salesforce-pages-developers-guide/checkmark_16x16.png) | ![checkmark](https://a.sfdcstatic.com/developer-website/sfdocs/platform/media/salesforce-pages-developers-guide/checkmark_16x16.png) |

## Setting Variable Values without a Controller

This example sets `myVariable` to the value `01010101` when the interview starts.

```visualforce
<apex:page>
    <flow:interview name="flowname">
        <apex:param name="myVariable" value="01010101"/>
    </flow:interview>
</apex:page>
```

## Setting Variable Values with a Standard Controller

You can use standard Visualforce controllers to set variables by passing in data from a record. This example sets the initial value of `myVariable` to the Visualforce expression `{!account}` when the interview starts.

```visualforce
<apex:page standardController="Account" tabStyle="Account">
    <flow:interview name="flowname">
        <apex:param name="myVariable" value="{!account}"/>
    </flow:interview>
</apex:page>
```

## Setting a Record Collection Variable Value with a Standard List Controller

Because record collection variables represent an array of values, you must use a standard list controller or a custom Apex controller. This example sets `myCollection` to the value of `{!accounts}` when the interview starts.

```visualforce
<apex:page standardController="Account" tabStyle="Account" recordSetVar="accounts">
    <flow:interview name="flowname">
        <apex:param name="myCollection" value="{!accounts}"/>
    </flow:interview>
</apex:page>
```

## Setting Variable Values with a Custom Apex Controller

For finer control over your Visualforce page than a standard controller allows, write a custom Apex controller that sets the variable value, and then reference that controller in your Visualforce page. This example uses Apex to set `myVariable` to a specific account’s Id when the interview starts.

```apex_code
public class MyCustomController {
    public Account apexVar {get; set;}

    public MyCustomController() {
        apexVar = [
            SELECT Id, Name FROM Account
            WHERE Name = 'Acme' LIMIT 1];
    }
}
```

```visualforce
<apex:page controller="MyCustomController">
    <flow:interview name="flowname">
        <apex:param name="myVariable" value="{!apexVar}"/>
    </flow:interview>
</apex:page>
```

This example uses Apex to set a record collection variable `myAccount` to the `Id` and `Name` field values for every record with a `Name` of `Acme`.

```apex_code
public class MyCustomController {
    public Account[] myAccount { 
        get {
            return [ 
                SELECT Id, Name FROM account 
                WHERE Name = 'Acme'
                ORDER BY Id
            ] ;
        }
        set {
            myAccount = value;
        }
    }
    public MyCustomController () {
    }
}
```

```visualforce
<apex:page id="p" controller="MyCustomController">
    <flow:interview id="i" name="flowname">
        <apex:param name="accountColl" value="{!myAccount}"/>
    </flow:interview>
</apex:page>
```

## Setting Variable Values with an Interview Map

This example uses an Interview map to set the value for `accVar` to a specific account’s Id when the interview starts.

```apex_code
public class MyCustomController {
    public Flow.Interview.TestFlow myflow { get; set; }

     public MyCustomController() {
        Map<String, Object> myMap = new Map<String, Object>();
        myMap.put('accVar', [SELECT Id FROM Account 
                             WHERE Name = 'Acme' LIMIT 1]);
        myflow = new Flow.Interview.ModemTroubleShooting(myMap);
    }
}
```

```visualforce
<apex:page controller="MyCustomController">
    <flow:interview name="flowname" interview="{!myflow}"/>
</apex:page>
```

Here’s a similar example that sets the value for `accVar` to a new account when the interview starts.

```apex_code
public class MyCustomController {
    public Flow.Interview.TestFlow myflow { get; set; }

     public MyCustomController() {
        Map<String, List<Object>> myMap = new Map<String, List<Object>>();
        myMap.put('accVar', new Account(name = 'Acme'));
        myflow = new Flow.Interview.ModemTroubleShooting(myMap);
    }
}
```

```visualforce
<apex:page controller="MyCustomController">
    <flow:interview name="flowname" interview="{!myflow}"/>
</apex:page>
```

This example uses a map to add two values to a string collection variable (`stringCollVar`) and two values to a number collection variable (`numberCollVar`).

```apex_code
public class MyCustomController {
    public Flow.Interview.flowname MyInterview { get; set; }

    public MyCustomController() {
        String[] value1 = new String[]{'First', 'Second'};
        Double[] value2 = new Double[]{999.123456789, 666.123456789};
        Map<String, Object> myMap = new Map<String, Object>();
        myMap.put('stringCollVar', value1);
        myMap.put('numberCollVar', value2);
        MyInterview = new Flow.Interview.flowname(myMap);
    }
}
```

```visualforce
<apex:page controller="MyCustomController">
    <flow:interview name="flowname" interview="{!MyInterview}" />
</apex:page>
```