Blazor onchange event with select dropdown

Blazor onchange event with select dropdown

To handle the onchange event with a select dropdown in Blazor, you can follow these steps:

  1. Add a select dropdown to your Blazor component.

    <select @onchange="HandleChange"> <option value="option1">Option 1</option> <option value="option2">Option 2</option> <option value="option3">Option 3</option> </select>

  2. Define the HandleChange method in your Blazor component.

    void HandleChange(ChangeEventArgs e) { var selectedValue = e.Value.ToString(); // do something with the selected value }

    The ChangeEventArgs parameter contains the value of the selected option.

  3. Optionally, you can bind the selected value to a property in your Blazor component.

    <select @bind="SelectedValue"> <option value="option1">Option 1</option> <option value="option2">Option 2</option> <option value="option3">Option 3</option> </select> 
    string SelectedValue { get; set; } void HandleChange(ChangeEventArgs e) { SelectedValue = e.Value.ToString(); }

    In this example, the SelectedValue property is updated with the selected value. The @bind directive binds the selected value to the SelectedValue property.

Examples

  1. "Blazor onchange event with select dropdown"

    • Code:
      <select @onchange="HandleSelectChange"> <option value="option1">Option 1</option> <option value="option2">Option 2</option> </select> @code { void HandleSelectChange(ChangeEventArgs e) { var selectedValue = e.Value.ToString(); // Your code here } }
    • Description: Basic example demonstrating the @onchange event with a select dropdown in Blazor.

  2. "Blazor onchange event with enum in select dropdown"

    • Code:
      <select @onchange="HandleSelectChange"> @foreach (var enumValue in Enum.GetValues(typeof(MyEnum))) { <option value="@enumValue">@enumValue</option> } </select> @code { void HandleSelectChange(ChangeEventArgs e) { var selectedEnumValue = Enum.Parse<MyEnum>(e.Value.ToString()); // Your code here } public enum MyEnum { Option1, Option2 } }
    • Description: Illustrates using an enum in a select dropdown with the @onchange event in Blazor.

  3. "Blazor onchange event with dynamic options in select dropdown"

    • Code:
      <select @onchange="HandleSelectChange"> @foreach (var option in dropdownOptions) { <option value="@option.Value">@option.Text</option> } </select> @code { List<SelectOption> dropdownOptions = new List<SelectOption> { new SelectOption { Value = "option1", Text = "Option 1" }, new SelectOption { Value = "option2", Text = "Option 2" } }; void HandleSelectChange(ChangeEventArgs e) { var selectedValue = e.Value.ToString(); // Your code here } public class SelectOption { public string Value { get; set; } public string Text { get; set; } } }
    • Description: Uses a dynamic list of options in a select dropdown with the @onchange event in Blazor.

  4. "Blazor onchange event with cascading dropdowns"

    • Code:
      <select @onchange="HandleParentSelectChange"> @foreach (var parentOption in parentOptions) { <option value="@parentOption.Value">@parentOption.Text</option> } </select> <select @onchange="HandleChildSelectChange"> @foreach (var childOption in childOptions) { <option value="@childOption.Value">@childOption.Text</option> } </select> @code { List<SelectOption> parentOptions = new List<SelectOption> { new SelectOption { Value = "parent1", Text = "Parent 1" }, new SelectOption { Value = "parent2", Text = "Parent 2" } }; List<SelectOption> childOptions = new List<SelectOption> { new SelectOption { Value = "child1", Text = "Child 1" }, new SelectOption { Value = "child2", Text = "Child 2" } }; void HandleParentSelectChange(ChangeEventArgs e) { var selectedValue = e.Value.ToString(); // Logic to update child dropdown options based on the selected parent option } void HandleChildSelectChange(ChangeEventArgs e) { var selectedValue = e.Value.ToString(); // Your code here } public class SelectOption { public string Value { get; set; } public string Text { get; set; } } }
    • Description: Demonstrates using the @onchange event with cascading dropdowns in Blazor.

  5. "Blazor onchange event with multi-select dropdown"

    • Code:
      <select multiple @onchange="HandleMultiSelectChange"> @foreach (var option in multiSelectOptions) { <option value="@option.Value">@option.Text</option> } </select> @code { List<SelectOption> multiSelectOptions = new List<SelectOption> { new SelectOption { Value = "option1", Text = "Option 1" }, new SelectOption { Value = "option2", Text = "Option 2" } }; List<string> selectedValues = new List<string>(); void HandleMultiSelectChange(ChangeEventArgs e) { var selectedOption = e.Value.ToString(); // Logic to handle multi-select changes } public class SelectOption { public string Value { get; set; } public string Text { get; set; } } }
    • Description: Shows how to handle the @onchange event with a multi-select dropdown in Blazor.

  6. "Blazor onchange event with pre-selected option"

    • Code:
      <select @onchange="HandleSelectChange"> @foreach (var option in selectOptions) { <option value="@option.Value" selected="@option.IsSelected">@option.Text</option> } </select> @code { List<SelectOption> selectOptions = new List<SelectOption> { new SelectOption { Value = "option1", Text = "Option 1", IsSelected = true }, new SelectOption { Value = "option2", Text = "Option 2" } }; void HandleSelectChange(ChangeEventArgs e) { var selectedValue = e.Value.ToString(); // Your code here } public class SelectOption { public string Value { get; set; } public string Text { get; set; } public bool IsSelected { get; set; } } }
    • Description: Demonstrates using the @onchange event with a pre-selected option in a select dropdown in Blazor.

  7. "Blazor onchange event with delayed execution"

    • Code:
      <select @onchange="@(async e => await HandleSelectChangeAsync(e))"> @foreach (var option in selectOptions) { <option value="@option.Value">@option.Text</option> } </select> @code { List<SelectOption> selectOptions = new List<SelectOption> { new SelectOption { Value = "option1", Text = "Option 1" }, new SelectOption { Value = "option2", Text = "Option 2" } }; async Task HandleSelectChangeAsync(ChangeEventArgs e) { await Task.Delay(1000); // Simulate delay var selectedValue = e.Value.ToString(); // Your code here } public class SelectOption { public string Value { get; set; } public string Text { get; set; } } }
    • Description: Uses an asynchronous method with @onchange to handle the select dropdown change event with delayed execution in Blazor.

  8. "Blazor onchange event with real-time search"

    • Code:
      <input type="text" @oninput="HandleSearchInput" /> <select @onchange="HandleSelectChange"> @foreach (var option in filteredOptions) { <option value="@option.Value">@option.Text</option> } </select> @code { List<SelectOption> allOptions = new List<SelectOption> { new SelectOption { Value = "option1", Text = "Option 1" }, new SelectOption { Value = "option2", Text = "Option 2" } }; List<SelectOption> filteredOptions = new List<SelectOption>(); void HandleSearchInput(ChangeEventArgs e) { var searchText = e.Value.ToString(); filteredOptions = allOptions .Where(option => option.Text.Contains(searchText, StringComparison.OrdinalIgnoreCase)) .ToList(); } void HandleSelectChange(ChangeEventArgs e) { var selectedValue = e.Value.ToString(); // Your code here } public class SelectOption { public string Value { get; set; } public string Text { get; set; } } }
    • Description: Implements real-time search functionality with @oninput and @onchange events for a select dropdown in Blazor.

  9. "Blazor onchange event with server-side data retrieval"

    • Code:
      <select @onchange="@(async e => await HandleSelectChangeAsync(e))"> @foreach (var option in await GetOptionsFromServer()) { <option value="@option.Value">@option.Text</option> } </select> @code { async Task<List<SelectOption>> GetOptionsFromServer() { // Logic to retrieve options from the server } async Task HandleSelectChangeAsync(ChangeEventArgs e) { var selectedValue = e.Value.ToString(); // Your code here } public class SelectOption { public string Value { get; set; } public string Text { get; set; } } }
    • Description: Demonstrates handling the select dropdown change event with server-side data retrieval in Blazor.

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