无法将参数值从字符串转换为DateTime的Int32

Question

I have a C# form linked to an SQL database, and for one of the columns I wish to insert the current date each time a new row is added. I am baffled because at one point this code was doing exactly what I wanted, and then after changing a few things it now keeps throwing the error "Failed to convert parameter value from a String to a Int32." and I don't know what happened. Here is my table definition. I know the value types are probably a bit arbitrary, but all I care about is that the date is stored as a string.

CREATE TABLE [dbo].[InvTable] (
[ID]       INT           IDENTITY (1, 1) NOT NULL,
[Item]     NVARCHAR (50) NULL,
[QuantRem] INT           NULL,
[Type]     NCHAR (10)    NULL,
[DateOrd]  NCHAR(10)    NULL,
[QuantOrd] INT           NULL,
[Received] BIT           NULL,
[DateRec]  NCHAR(10)    NULL,
PRIMARY KEY CLUSTERED ([ID] ASC)
);

And the code on the form is below. The second date will be defined differently later, but my primary concern is getting rid of the error in the title.

    private void Submitbutton1_Click(object sender, EventArgs e)
    {
        if (string.IsNullOrWhiteSpace(textBox1.Text))
        {
            MessageBox.Show("Cannot Submit Empty Request");
            return;
        }
        if (comboBox1.SelectedItem == null)
        {
            MessageBox.Show("Please Use Drop Down Menu To Select Item Category");
            return;
        }
        SqlDataAdapter da = new SqlDataAdapter();
        da.InsertCommand = new SqlCommand("INSERT INTO InvTable VALUES(@Item, @QuantRem, @Type, @DateReq, @QuantOrd, @Received, @DateRec)", con);
        da.InsertCommand.Parameters.Add("@Item", SqlDbType.NChar).Value = textBox1.Text;
        da.InsertCommand.Parameters.Add("@QuantRem", SqlDbType.Int).Value = textBox2.Text;
        da.InsertCommand.Parameters.Add("@Type", SqlDbType.NChar).Value = comboBox1.Text;
        da.InsertCommand.Parameters.Add("@DateReq", SqlDbType.NChar).Value = DateTime.Today.ToString("d");
        da.InsertCommand.Parameters.Add("@QuantOrd", SqlDbType.Int).Value = 0;
        da.InsertCommand.Parameters.Add("@Received", SqlDbType.Bit).Value = 0;
        da.InsertCommand.Parameters.Add("@DateRec", SqlDbType.NChar).Value = DateTime.Today.ToString("d");
        con.Open();
        da.InsertCommand.ExecuteNonQuery();
        da.SelectCommand = new SqlCommand("SELECT * FROM InvTable WHERE Received=0", con);
        con.Close();
        ds.Clear();
        da.Fill(ds);
        invTableDataGridView.DataSource = ds.Tables[0];
        textBox1.Clear();
    }

So this code used to work at one point, giving me a string "07/20/2015", but now it just gives me an error.

Answer 1

You are a victim of choosing the wrong data type .

Change your DateOrd and DateRec column types to date type and pass your DateTime.Today directly to your parameterized query (since you keep only date part of a DateTime ).

[DateOrd]  date    NULL,
...
...
[DateRec]  date   NULL,

and

da.InsertCommand.Parameters.Add("@DateReq", SqlDbType.Date).Value = DateTime.Today;
da.InsertCommand.Parameters.Add("@DateRec", SqlDbType.Date).Value = DateTime.Today;

Also for QuantRem column, looks like you need to parse textBox2.Text value to int before you pass it as a parameter.

da.InsertCommand.Parameters.Add("@QuantRem", SqlDbType.Int).Value = int.Parse(textBox2.Text);

Don't forget to use using statement to dispose your connections, commands and adapters automatically instead of calling Close methods manually.

Answer 2

As others have said, don't use text when you could/should be using an actual date type ... it will save you a lot of hassle now and in the future.

But your actual error is more likely to be this line: da.InsertCommand.Parameters.Add("@QuantRem", SqlDbType.Int).Value = textBox2.Text;

Where you are taking text and trying to set an integer parameter. Convert that text to an integer, and then set your integer parameter.