Xamarin.Android: GridLayout not displaying column items

I'm working on a Xamarin.Android app, and I wish to use a GridLayout to display a simple form. However, the GridLayout doesn't display all the entry boxes found in the second column. If I place the items ( EditText Controls) in Column 0, I they become visible. But if I set layout_Column="1, they disappear. Does anyone have a suggestion? Below is my code

<?xml version="1.0" encoding="utf-8"?>

<GridLayout
    android:rowCount="7"
    android:columnCount="3"
    android:columnOrderPreserved="false"
    android:layout_marginLeft="25dp"
    android:layout_marginRight="15dp"
    android:layout_marginTop="30dp"
    android:layout_marginBottom="8dp"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="center_vertical"
    android:orientation="horizontal"
    >
    <TextView
        android:text="Name:"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:layout_row="0"
        android:layout_column="0"
        android:textSize="20dp"
        android:layout_marginTop="5dp"
        android:layout_marginRight="5dp"
        />
    <EditText
        android:id="@+id/nameTxt"
        android:inputType="text"
        android:text="Item Name"
        android:layout_row="0"
        android:layout_column="1"
        android:layout_marginTop="5dp"
        android:layout_marginLeft="8dp"
        android:textSize="20dp"
        android:minWidth="200dp"
        android:padding="2dp"
        android:layout_width="wrap_content"
        android:background="#eee"
        android:textColor="#001"
    />
    <TextView
        android:text="Unit Price:"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:layout_row="1"
        android:layout_column="0"
        android:layout_marginTop="5dp"
        android:textSize="20dp"
        android:layout_marginRight="5dp"
        />
    <EditText
        android:id="@+id/priceTxt"
        android:text="Unit Price"
        android:layout_row="1"
        android:layout_marginTop="5dp"
        android:layout_marginLeft="8dp"
        android:layout_column="1"
        android:textColor="#0000"
        android:textSize="20dp"
        android:layout_width="fill_parent"
    />
    <TextView
        android:text="Category:"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:layout_row="2"
        android:layout_column="0"
        android:layout_marginTop="5dp"
        android:textSize="20dp"
        android:layout_marginRight="5dp"
        />
    <Spinner
        android:layout_row="2"
        android:layout_column="1"
        android:padding="1dp"
        android:entries="@array/item_category"
        android:backgroundTint="#D11F08"
        android:layout_marginLeft="8dp"
        android:layout_marginTop="5dp"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:id="@+id/categorySpinner" />
    <TextView
        android:text="Quantity:"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:layout_row="3"
        android:layout_column="0"
        android:textSize="20dp"
        android:layout_marginTop="5dp"
        android:layout_marginRight="5dp"
        />
    <EditText
        android:id="@+id/qtyTxt"
        android:text="Quantity"
        android:layout_row="3"
        android:layout_marginTop="5dp"
        android:layout_marginLeft="8dp"
        android:layout_column="1"
        android:textColor="#0000"
        android:textSize="20dp"
        android:layout_width="fill_parent"
    />
    <TextView
        android:text="Total Price:"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:layout_row="4"
        android:layout_column="0"
        android:textSize="20dp"
        android:layout_marginTop="5dp"
        android:layout_marginRight="5dp"
        />
    <EditText
        android:id="@+id/totalPriceTxt"
        android:text="Total Price"
        android:layout_row="4"
        android:layout_marginTop="5dp"
        android:layout_marginLeft="8dp"
        android:layout_column="1"
        android:textColor="#0000"
        android:textSize="20dp"
        android:layout_width="fill_parent"
    />
    <Button
        android:id="@+id/saveBtn"
        android:text="Save"
        android:layout_row="5"
        android:layout_column="0"
        android:background="@drawable/buttonstyle"
        android:layout_marginTop="5dp"
        android:layout_marginBottom="100dp"
        android:layout_marginLeft="30dp"
        android:layout_marginRight="30dp"
        android:layout_width="match_parent"
        />
</GridLayout>