Value not getting updated on click of Column Chart field Links

load(
  local!a,
  local!b,
  local!c,
  local!data: {
    {
      data: {
        10,
        20,
        30
      }
    },
    {
      data: {
        20,
        10,
        30
      }
    },
    {
      data: {
        40,
        10,
        15
      }
    }
  },
  local!label: {
    "Bar-1",
    "Bar-2",
    "Bar-3"
  },
  {
    a!columnChartField(
      label: "Multi-Category Chart",
      categories: {
        "Cat-1",
        "Cat-2",
        "Cat-3"
      },
      stacking: "NORMAL",
      series: {
        a!forEach(
          items: local!data,
          expression: a!chartSeries(
            label: local!label[fv!index],
            data: fv!item.data,
            links: a!forEach(
              items: local!data,
              expression: a!dynamicLink(
                saveInto: {
                  a!save(
                    local!a,
                    10
                  ),
                  a!save(
                    local!b,
                    20
                  ),
                  a!save(
                    local!c,
                    30
                  )
                }
              )
            )
          )
        )
      }
    ),
    a!textField(
      value: local!a
    )
  }
)

In place of save(local!a,"10")) use a!save(local!a,"10")) in your code snippet

Note that with this code, the "a!forEach" call you've added doesn't do very much, because it's saving the same hardcoded values into the three local variables (a - c) regardless of which item in the chart is clicked.

If you wish to populate these with the actual column data when clicked, you'd replace the hardcoded values with fv!item.data[index], as below:

load(
  local!a,
  local!b,
  local!c,
  local!data: {
    {
      data: {
        10,
        20,
        30
      }
    },
    {
      data: {
        20,
        10,
        30
      }
    },
    {
      data: {
        40,
        10,
        15
      }
    }
  },
  local!label: {
    "Bar-1",
    "Bar-2",
    "Bar-3"
  },
  {
    a!columnChartField(
      label: "Multi-Category Chart",
      categories: {
        "Cat-1",
        "Cat-2",
        "Cat-3"
      },
      stacking: "NORMAL",
      series: {
        a!forEach(
          items: local!data,
          expression: a!chartSeries(
            label: local!label[fv!index],
            data: fv!item.data,
            links: a!forEach(
              items: local!data,
              expression: a!dynamicLink(
                saveInto: {
                  a!save(
                    local!a,
                    fv!item.data[1]
                  ),
                  a!save(
                    local!b,
                    fv!item.data[2]
                  ),
                  a!save(
                    local!c,
                    fv!item.data[3]
                  )
                }
              )
            )
          )
        )
      }
    ),
    a!textField(
      value: "a: " & local!a & char(10) &
        "b: " & local!b & char(10) &
        "c: " & local!c,
      readOnly: true()
    )
  }
)

Yes, I have a!save in my code, but still not working.

Please try the example I provided above (perhaps in a new interface editor) and see if it does what you were hoping for (since i'm a little unclear on what your desired outcome is) -- and see if it might help you figure out how to correctly implement your saves.

Got the solution. It's working fine now. Thanks everyone.