如何修复C# WinForm中‘无法将方法组Focus转换为非委托类型int’错误

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Why You're Getting That Error #

The error Cannot convert method group 'Focus' to non-delegate type 'int' comes from two key mistakes in your code:

• Your tst1 variable is hardcoded to 0 and has no link to the currently active tab page.
• Tabp1.Focus is a method (it returns a boolean indicating if focus was set), not an integer value. You can't use a method as a case condition when switching on an int.

Correct Implementation: Target the Active Tab #

To make your save button only act on the tab the user is currently viewing, you need to use your TabControl's SelectedTab (checks the tab's name) or SelectedIndex (checks the tab's position) property. Here's the fixed code:

private void BtnSave_Click(object sender, EventArgs e)
{
    // Get the currently selected tab page from your TabControl
    // Replace "tabControl1" with the actual name of your TabControl
    var activeTab = tabControl1.SelectedTab;

    // Switch based on the tab's Name property (matches the Name you set in the designer)
    switch (activeTab.Name)
    {
        case "Tabp1":
            // Add the new item to ListView
            ListViewItem item = listView1.Items.Add(NameTB.Text);
            item.SubItems.Add(FamilTB.Text);
            item.SubItems.Add(AgeMTB.Text);
            item.SubItems.Add(ForceStatusCobx.Text);
            item.SubItems.Add(ForceTypeCobx.Text);
            item.SubItems.Add(PhNumMTB.Text);
            item.SubItems.Add(PirsonaliCodeMTB1.Text);

            // Clear input fields (fixed a typo: "ForceTypCobx" → "ForceTypeCobx")
            NameTB.Text = string.Empty;
            FamilTB.Text = string.Empty;
            AgeMTB.Text = string.Empty;
            ForceStatusCobx.Text = string.Empty;
            ForceTypeCobx.Text = string.Empty;
            PhNumMTB.Text = string.Empty;
            PirsonaliCodeMTB1.Text = string.Empty;

            MessageBox.Show("INFO IS register!", "Successful operation", MessageBoxButtons.OK, MessageBoxIcon.Asterisk);
            break;

        case "Tabp2":
            // Add save logic for your second tab here
            break;

        // Add more cases for additional tabs as needed
    }
}

Alternative: Use SelectedIndex (By Tab Position) #

If you prefer to switch based on the tab's position in the TabControl (0 for first tab, 1 for second, etc.), you can use SelectedIndex instead:

private void BtnSave_Click(object sender, EventArgs e)
{
    switch (tabControl1.SelectedIndex)
    {
        case 0: // This is the first tab (Tabp1)
            // Same save logic as above
            break;
        case 1: // Second tab
            // Corresponding save code
            break;
    }
}

Key Notes #

• Make sure tabControl1 matches the actual name of your TabControl component in the form designer.
• Double-check the Name property of your TabPages (e.g., Tabp1) to ensure it matches the string in the case statement.
• I fixed a typo in your original code: ForceTypCobx.Text was misspelled (missing an 'e' → ForceTypeCobx), which would have caused another compile error.

内容的提问来源于stack exchange，提问作者Amir