C# 无法将“system.string”类型的对象转换为“system.int32”类型

Question

I am getting the error unable to cast object of type 'system.string' to type 'system.int32' when retrieving a varchar column that contains data and trying it to display it in a ComboBox.

Here is my code:

private void GetFinancialCatDeactivate(int active)
        {
            try
            {
                using (var Connect = new SqlConnection(connstr))
                {
                    Connect.Open();
                    using (var Command = new SqlCommand("[dbo].[spParametresFinancesTb_GetCategories]", Connect))
                    {
                        Command.CommandType = CommandType.StoredProcedure;
                        Command.Parameters.Add("@active", SqlDbType.VarChar).Value = active;
                        SqlDataReader dr = Command.ExecuteReader();
                        while (dr.Read())
                        {
                            string catlist = dr.GetString(0)

                            ComboBoxFinanceNameDeactivate.Items.Add(catlist);
                            ComboBoxFinanceNameDeactivate.Text = catlist;
                            ComboBoxFinanceDefaultNameEdit.Items.Add(catlist);
                            ComboBoxFinanceDefaultNameEdit.Text = catlist;                            

                        }
                        dr.Close();
                    }

                    Connect.Close();
                }
            }
            catch (Exception ex)
            {

                MessageBox.Show(ex.Message);
            }
        }

The code is executing a stored procedure which is here:

ALTER PROCEDURE [dbo].[spParametresFinancesTb_GetCategories]
(
    @active numeric(1)
 )
AS
BEGIN
    BEGIN TRY
        SET NOCOUNT ON
            BEGIN
                    select category
                    from dbo.PARAMETRES_FINANCES 
                    where active = @active;
                END;
    END TRY
    BEGIN CATCH     
        SELECT
        ERROR_PROCEDURE () as ProcedureErreur,
        ERROR_MESSAGE () as MessageErreur,
        ERROR_LINE () as LigneErreur,
        ERROR_SEVERITY () as SeveriteErreur
    END CATCH
END;

The error is appearing here: ComboBoxFinanceDefaultNameEdit.Text = catlist; in the code-behind.

I find it very weird since the fist combobox is not displaying the error.

Here is how both comboboxes are made (XAML):

<ComboBox Name="ComboBoxFinanceDefaultNameEdit" Style="{StaticResource ComboBoxStyle}" SelectionChanged="ComboBoxFinanceDefaultNameEdit_SelectionChanged"/>

<ComboBox Name="ComboBoxFinanceNameDeactivate" Grid.Column="1" Style="{StaticResource ComboBoxStyle}"/>

I tried changing the ComboBoxFinanceDefaultNameEdit.Text = catlist; to ComboBoxFinanceDefaultNameEdit.SelectedItem= catlist; but it dind't change a thing.

Any idea what is going on here?

I am on .Net Core 3.1.101

EDIT

I have updated the question to add more information about the problem.

EDIT 2

I have noticed that the problem is appearing mainly on comboboxes where I have implemented a selectionchanged event. Without this event, no error. Still investigating how to fix this.

EDIT 3

I would like to mention that the error is shown as a messagebox. When I debug, it doesn't throw an exception but rather a messagebox. However, the data is still displayed in the combobox. The combobox where this problem appears is the one where I have a selectionchange event

Answer 1

I think the problem is with the @active parameter. You see you have defined it as SqlDbType.VarChar

 Command.Parameters.Add("@active", SqlDbType.VarChar).Value = active;

But in your stored procedure you have marked it as @active numeric(1) .