Make a json for grid data and send to back end - extjs

Question

I need to make a json string for grid table field list.and need to send them java back end.
I have to send
id,
name,
listOfProjects,
listOfProjects contains following list,this list may contains number of items.
prjId,
prjName
Please tell me how to create a json string ?
I tried with following code sample
var dataStr = new Object();
dataStr.id=myId;
dataStr.name="myName";
dataStr.plist = new Array();
dataStr.plist[0].prjId=1stId;
dataStr.plist[0].prjName="1stName";
dataStr.plist[1].prjId=2ndId;
dataStr.plist[1].prjName="2ndName";
dataStr.plist[2].prjId=3rdId;
dataStr.plist[2].prjName="3rdName";
var data = Ext.JSON.encode(dataStr);
Ext.Ajax.request({
url : '/E2EAT/authentication/userdetails.json',
method : "GET",
headers: {
'Content-Type': 'application/json'
},
params : 'data=' + data ,
useDefaultXhrHeader : false,
withCredentials: true,
});
I can use the code above, but I need to iterate grid
1 . Please let me know how can I iterate a grid with sencha?
2 . What's the best method to make json string and send back end?

Answer 1

Ext gives you two loop functions: Ext.each, and Ext.iterate for objects.
To iterate over columns of a grid, you can use the Ext.grid.Panel#columns array property, containing Columns instances. For example, in order to build a list of visible columns, you can do:
var visibleColumns = [];
Ext.each(grid.columns, function(column) {
// Only columns bound to a field (exludes actions colutions, etc.)
if (!Ext.isEmpty(column.dataIndex)) {
if (column.isVisible()) {
visibleColumns.push({
field: column.dataIndex
,label: column.text
});
}
}
});
A grid doesn't necessarily have a column for every field of the underlying store, and it can have extra columns for custom rendering, actions, numbering, selection, etc. So, you may want to iterate over the fields of the store, instead of the grid columns. In this case, we'd be working we've Ext.data.Field objects:
// Get a ref to the store's model. Stores always have models; even
// if none is specified explicitly, one is created implicitly.
var model = grid.getStore().model;
var fieldNames = [];
Ext.each(model.getFields(), function(field) {
fieldNames.push(field.name);
});
Finally, you turn your data into JSON using Ext.encode. Also, you don't have to build the URL query (params) yourself, which would give more flexibility to other parts of your code that may need to add some params:
Ext.Ajax.request({
...
params: {
data: Ext.encode(rawData)
}
});
For a POST request, you can also use the jsonData property, to save yourself the json encoding:
Ext.Ajax.request({
...
jsonData: {
data: rawData
}
});
In many cases, though, it will be preferable to use a store with an appropriately configured data proxy and writer rather than a direct AJAX request.