# EventData

```python
gradio.EventData(···)
```

### Description

When gr.EventData or one of its subclasses is added as a type hint to an argument of a prediction function, a gr.EventData object will automatically be passed as the value of that argument. The attributes of this object contains information about the event that triggered the listener. The gr.EventData object itself contains a `.target` attribute that refers to the component that triggered the event, while subclasses of gr.EventData contains additional attributes that are different for each class.

### Example Usage

```python
import gradio as gr

with gr.Blocks() as demo:
    table = gr.Dataframe([[1, 2, 3], [4, 5, 6]])
    gallery = gr.Gallery([("cat.jpg", "Cat"), ("dog.jpg", "Dog")])
    textbox = gr.Textbox("Hello World!")
    statement = gr.Textbox()

    def on_select(value, evt: gr.EventData):
        return f"The {evt.target} component was selected, and its value was {value}."

    table.select(on_select, table, statement)
    gallery.select(on_select, gallery, statement)
    textbox.select(on_select, textbox, statement)

demo.launch()
```

### Attributes

| Parameter | Type | Default | Description |
|-----------|------|---------|-------------|
| `target` | `Block \| None` | `` | The component object that triggered the event. Can be used to distinguish multiple components bound to the same listener. |
### Demos

**gallery_selections**

[See demo on Hugging Face Spaces](https://huggingface.co/spaces/gradio/gallery_selections)

```python
import gradio as gr
import numpy as np

with gr.Blocks() as demo:
    imgs = gr.State()
    gallery = gr.Gallery(allow_preview=False)

    def deselect_images():
        return gr.Gallery(selected_index=None)

    def generate_images():
        images = []
        for _ in range(9):
            image = np.ones((100, 100, 3), dtype=np.uint8) * np.random.randint(
                0, 255, 3
            )  # image is a solid single color
            images.append(image)
        return images, images

    demo.load(generate_images, None, [gallery, imgs])

    with gr.Row():
        selected = gr.Number(show_label=False)
        darken_btn = gr.Button("Darken selected")
    deselect_button = gr.Button("Deselect")

    deselect_button.click(deselect_images, None, gallery)

    def get_select_index(evt: gr.SelectData):
        return evt.index

    gallery.select(get_select_index, None, selected)

    def darken_img(imgs, index):
        index = int(index)
        imgs[index] = np.round(imgs[index] * 0.8).astype(np.uint8)
        return imgs, imgs

    darken_btn.click(darken_img, [imgs, selected], [imgs, gallery])

if __name__ == "__main__":
    demo.launch()
```

**tictactoe**

[See demo on Hugging Face Spaces](https://huggingface.co/spaces/gradio/tictactoe)

```python
import gradio as gr

with gr.Blocks() as demo:
    turn = gr.Textbox("X", interactive=False, label="Turn")
    board = gr.Dataframe(value=[["", "", ""]] * 3, interactive=False, type="array")

    def place(board: list[list[int]], turn, evt: gr.SelectData):  
        if evt.value:
            return board, turn
        board[evt.index[0]][evt.index[1]] = turn
        turn = "O" if turn == "X" else "X"
        return board, turn

    board.select(place, [board, turn], [board, turn], show_progress="hidden")

if __name__ == "__main__":
    demo.launch()
```

- [Blocks And Event Listeners](https://www.gradio.app/guides/blocks-and-event-listeners/)