To get the Dropdown field value

[nishanth mathialagan]

Hello,

.appendField("Form selection")

.appendField(  new Blockly.FieldDropdown(forms),'formtitle')

 .appendField("FieldID")

.appendField(  new Blockly.FieldDropdown(option), 'fieldId')

The above one is my working blockly code and scrrenshot.I need to get the value form form selection depon upon i will get field values from that selection and display the options available in FieldID

.For that if i write function on fieldID like function(){...},How can i get the value from Form Selection in this whenever change.

Thank you

[nishanth mathialagan]

like in Form selection if select Form1  =>get options from localstorage("form1") contains(["firstname","firstname"],...)option need to display in fieldID.If i select Form2=> get options from localstorage("form2") contains(["some","some"],...)option need to display in fieldID like dynmaic.for that how can i get select value from form selection to fieldID

[Beka Westberg]

Hello!

So it seems like you want to create a dynamic dropdown which depends on the value of another dropdown.

Firstly, to get the value of the first dropdown you can do `block.getFieldValue('formtitle')`.

Then you can use this to create your dynamic dropdown generator. For example, you could do something like:

```

Blockly.Blocks['my_block_type'] = {

  init: function() {

    this.appendDummyInpot()

.appendField("Form selection")

.appendField(  new Blockly.FieldDropdown(forms),'formtitle')

 .appendField("FieldID")

.appendField(  new Blockly.FieldDropdown(this.generate), 'fieldId')

  },

  // `this` is the 'fieldId' dropdown field

  generate: function() {

     const block = this.getSourceBlock();

     const form = block.getFieldValue('formtitle');

     const options = getOptionsFromForm(form); // some function to get the options.

     return options;

  }

}

```

I hope that helps! If you have any further questions please reply!
--Beka

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[nishanth mathialagan]

Hi Beka ,

  It throwing error in getFieldValue..

But its not empty or Null.

Check my code

 init: function() {

 this.appendDummyInput()

    .appendField("Form selection")

    .appendField(new Blockly.FieldDropdown(this.newgenerate),'formtitle')

    .appendField("FieldID")

    .appendField(  new Blockly.FieldDropdown(this.generate), 'fieldId')

},

 newgenerate:function(){

  var titleoptions=[]

  var forms=[]

  var title=localStorage.getItem("title1")

  titleoptions=JSON.parse(title)

  for(const x in titleoptions){

    forms[x]=[titleoptions[x],titleoptions[x]]

  }

  return forms

 },

generate:function() {

    const block = this.getSourceBlock();

    const form = block.getFieldValue('formtitle');

    var option=[];

    var field=localStorage.getItem(form)

    var fieldId=[]

    fieldId=JSON.parse(field)

    for(const x in fieldId){

      option[x]=[fieldId[x],fieldId[x]]

    }

    return option;

 },

};

Thank you

[Jason Schanker]

Hi,

this.getSourceBlock() will be null the first time before the field is mounted on the block.  I didn't get a chance to go through your code at the moment, but if you're working with dependent dropdowns, a previous discussion here might be useful: https://groups.google.com/g/blockly/c/uilMLN_VojA/m/sKd6LjNNAwAJ .

Hope this helps.

Best,

Jason

[nishanth mathialagan]

Thank you Beka and Jason. Jason that discussion helped me to solve my problem.Thank you